Bringing Useful Initiatives for Indian Land Development Act of 2017 or BUIILD Act of 2017 This bill amends the Native American Housing Assistance and Self-Determination Act of 1996 to modify the environmental review process used for certain affordable housing activities on Indian reservations. Specifically, the bill allows an Indian tribe that receives federal funds in addition to block grant amounts under the Act to assume all of the responsibilities for environmental review that would apply to the federal agencies providing funds for the project if the grant amount constitutes the largest single source of federal funds that the tribe reasonably expects to commit to the project at the time of environmental review. The bill reauthorizes through FY2025 the block grant program for affordable housing activities on Indian reservations, training and technical assistance for Indian tribes and tribally designated housing entities, and the Indian Housing Loan Guarantee Fund. In addition, the bill increases from 50 years to 99 years the term that tribal trusts or restricted lands may be leased for housing development and residential purposes. Funds provided under a grant under the Act may be used to meet matching or cost participation requirements under other federal or nonfederal programs.