Native American Housing Assistance and Self-Determination Reauthorization Act of 2020 This bill provides federal housing assistance to Indians and Native Hawaiians, including by reauthorizing through FY2031 and otherwise revising the Indian Housing Block Grant program and the Native Hawaiian Housing Block Grant program. It also provides statutory authority for the Tribal HUD-VASH program, which provides rental assistance and supportive services to Indian veterans who are homeless or at risk of homelessness.