IMPORTANT NOTICE TO SHAREHOLDERS OF NUVEEN SELECT TAX-FREE INCOME PORTFOLIO (NXP) NUVEEN SELECT TAX-FREE INCOME PORTFOLIO 2 (NXQ) AND NUVEEN SELECT TAX-FREE INCOME PORTFOLIO 3 (NXR) (EACH, A “FUND” AND TOGETHER, THE “FUNDS”) AUGUST 4, 2021 Although we recommend that you read the complete Joint Proxy Statement/Prospectus, for your convenience, we have provided a brief overview of the proposals to be voted on. Q. Why am I receiving the enclosed Joint Proxy Statement/Prospectus? A. You are receiving the Joint Proxy Statement/Prospectus as a holder of common shares of Nuveen Select Tax-Free Income Portfolio (the “Acquiring Fund”), Nuveen Select Tax-Free Income Portfolio 2 (“Select Tax-Free 2”) or Nuveen Select Tax-Free Income Portfolio 3 (“Select Tax-Free 3” and together with Select Tax-Free 2, the “Target Funds” or each individually, a “Target Fund”) in connection with the solicitation of proxies by each Fund’s Board of Trustees (each, a “Board” and each Trustee, a “Board Member”) for use at the annual meetings of shareholders of the Funds (each, an “Annual Meeting” and together, the “Annual Meetings”). At the Annual Meetings, shareholders of the Funds will be asked to vote on the following proposals: • (Each Target Fund) the reorganization of the Target Fund into the Acquiring Fund pursuant to an Agreement and Plan of Reorganization (the “Agreement”) under which the Target Fund will transfer substantially all of its assets and liabilities to the Acquiring Fund in exchange for newly issued common shares of the Acquiring Fund (each, a “Reorganization” and together, the “Reorganizations”); • (Acquiring Fund) the Reorganization with respect to each Target Fund; and • (Each Fund) the election of members of the Board. (The list of specific nominees for each Fund is contained in the enclosed Joint Proxy Statement/Prospectus.) Shareholders of each Target Fund are being solicited to vote on the election of four (4) Board Members at the Fund’s Annual Meeting so that the Target Fund may continue to be governed by its current Board Members, and avoid vacancies on the Board, in the event the Reorganization with respect to that Fund is not consummated in a timely manner. Each Fund’s Board unanimously recommends that you vote FOR each proposal that is applicable to your Fund. i Proposal Regarding the Reorganizations Q. Why has each Fund’s Board recommended the proposal? A. Nuveen Fund Advisors, LLC (“Nuveen Fund Advisors”), a subsidiary of Nuveen, LLC (“Nuveen”) and the Funds’ investment adviser, recommended the proposed Reorganizations as part of an ongoing initiative to rationalize the product offerings of Nuveen’s municipal closed-end funds. Each Fund’s Board considered its Fund’s Reorganization(s) in connection with this initiative and determined that such Reorganization(s) would be in the best interests of its Fund. Based on information provided by Nuveen Fund Advisors, each Fund’s Board believes that its Fund’s proposed Reorganization(s) may benefit the common shareholders of its Fund in a number of ways, including, among other things: • The ability to maintain the current investment objective, strategies and portfolio management of each Fund in the combined fund; • Greater secondary market liquidity and improved secondary market trading for common shares as a result of the combined fund’s greater share volume, which may lead to narrower bid-ask spreads and smaller trade-to-trade price movements; and • Cost savings in the form of lower net operating expenses, as certain fixed costs are spread over a larger asset base, and a lower effective management fee rate for shareholders of the combined fund due to, as applicable to each Fund, the Acquiring Fund’s lower fund-level management fee schedule (when compared to that of each Target Fund) and the achievement of additional breakpoints in the Acquiring Fund’s fund-level management fee schedule. For these reasons, each Fund’s Board, all of whose members are independent Board Members, has determined that its Fund’s Reorganization(s) are in the best interests of its Fund and has approved such Reorganization(s). Q. Do the Funds have similar investment objectives, policies and risks? A. Yes. The investment objective and policies of the Acquiring Fund are identical to those of the Target Funds. Each Fund’s investment objective is to provide current income exempt from regular federal income tax, consistent with preservation of capital. Under normal circumstances, each Fund will invest at least 80% of its assets in municipal securities and other related investments, the income from which is exempt from regular federal income tax and federal alternative minimum tax. Each Fund may invest up to 20% of its managed assets in municipal securities that pay interest that is taxable under the federal alternative minimum tax applicable to individuals. In addition, because the Acquiring Fund has the same investment objective and policies as the Target Funds, an investment in the Acquiring Fund following the Reorganizations will be subject to the same risks as an investment in each Target Fund prior to its Reorganization. ii See “Proposal No. 1—A. Synopsis—Comparison of the Acquiring Fund and the Target Funds—Investment Objectives and Policies” and “Proposal No. 1—B. Risk Factors” for more information. Q. How will the Reorganizations impact fees and expenses? A. Each Fund’s Board considered that the Reorganizations are expected to result in a lower effective fund-level management fee rate as a result of, as applicable, the adoption of the Acquiring Fund’s fund-level management fee schedule, which provides for a lower fund-level management fee rate at all asset levels than the Target Funds’ fund-level management fee schedules, and the achievement of additional breakpoints in the Acquiring Fund’s fund-level management fee schedule following the Reorganizations. Each Fund’s Board also considered that the Reorganizations are expected to result in economies of scale and a resulting reduction in certain other expenses. Based on information for each Fund’s fiscal year ended March 31, 2021 and assuming each Reorganization takes place, the pro forma expense ratio of the combined fund following the Reorganizations is estimated to be three basis points (0.03%) lower than the total expense ratio of the Acquiring Fund, eight basis points (0.08%) lower than the total expense ratio of Select Tax-Free 2 and nine basis points (0.09%) lower than the total expense ratio of Select Tax-Free 3. See the Comparative Fee Tables beginning on page 8 of the enclosed Joint Proxy Statement/ Prospectus for more detailed information regarding fees and expenses. See also “Additional Information About the Acquiring Fund” at page 82. Q. Will shareholders of the Funds have to pay any fees or expenses in connection with the Reorganizations? A. Yes. The Funds, and indirectly their common shareholders, will bear the costs of the Reorganizations, whether or not one or both of the Reorganizations are consummated. The allocation of the costs of the Reorganizations to the Funds is based on the expected benefits of the Reorganizations, including improvements in the secondary trading market for common shares and operating expense savings, if any, to Fund shareholders following the Reorganizations. The costs of the Reorganizations are estimated to be $875,000. These costs represent the estimated nonrecurring expenses of the Funds in carrying out their obligations under the Agreement and consist of management’s estimate of professional service fees, printing costs and mailing charges related to the proposed Reorganizations. Based on the expected benefits of the Reorganizations to each Fund, each of the Acquiring Fund, Select Tax-Free 2 and Select Tax-Free 3 is expected to be allocated approximately $225,000, $370,000 and $280,000, respectively, of expenses in connection with the Reorganizations. If the Reorganization with respect to a Target Fund is not consummated for any reason, including because the requisite shareholder approvals are not obtained, each of the Funds, and common shareholders of each of the Funds indirectly, will still bear the costs of the Reorganizations. iii Q. Will the Reorganizations constitute a taxable event for the Target Funds’ shareholders? A. No. Each Reorganization is intended to qualify as a tax-free “reorganization” for U.S. federal income tax purposes. It is expected that shareholders of a Target Fund who receive Acquiring Fund shares pursuant to a Reorganization will recognize no gain or loss for U.S. federal income tax purposes as a direct result of the Reorganization, except to the extent that a Target Fund common shareholder receives cash in lieu of a fractional Acquiring Fund common share. Prior to the closing of the Reorganizations, each Target Fund expects to declare a distribution of all of its net investment income and net capital gains, if any. All or a portion of such distribution made by a Target Fund may be taxable to that Target Fund’s shareholders for U.S. federal income tax purposes. In addition, to the extent that portfolio securities of a Target Fund are sold prior to the closing of the Reorganizations, such Target Fund may recognize gains or losses, which may increase or decrease the net capital gains or net investment income to be distributed by such Target Fund. However, because each Target Fund’s current portfolio composition is substantially similar to that of the Acquiring Fund, it is not currently expected that any significant portfolio sales will occur solely in connection with the Reorganizations (such sales are expected to be less than 5% of the assets of each Target Fund). Q. As a result of the Reorganizations, will common shareholders of the Target Funds receive new shares in exchange for their current shares? A. Yes. Upon the closing of the Reorganizations, Target Fund shareholders will become shareholders of the Acquiring Fund.