Prairie Band Potawatomi Nation Shab-eh-nay Band Reservation Settlement Act of 2021 This bill provides for the settlement of claims by the Prairie Band Potawatomi Nation relating to the Shab-eh-nay Band Reservation in northern Illinois. The reservation consists of 1,280 acres and, due to a sale in 1849, is currently occupied by the tribe and nontribe entities, including the State of Illinois, the Dekalb County government, and corporate entities. In particular, the bill recognizes the tribe's ownership of 130 acres of land within the reservation. Further, the bill extinguishes the tribe's title to the remainder of the reservation. Additionally, the bill requires the Department of the Interior to pay the tribe a specified amount as partial settlement of the tribe's claims for the tribe to promote economic development and land acquisition. The bill also outlines a process for subsequent payments to the tribe. The tribe may use these settlement funds to acquire up to 1,151 acres of land within or near the reservation. The bill authorizes the tribe to enter into agreements with the State of Illinois and local governments. It requires land that is located within the boundaries of the reservation and owned by state and local governments to be managed to protect any human or cultural remains.