Telecommunications Supply Chain Diversity Promotion Act This bill requires the National Telecommunications and Information Administration (NTIA) to establish an applied research open network architecture testbed at its Institute for Telecommunication Sciences, which shall develop and demonstrate network architectures and applications, equipment integration, and interoperability at scale. In addition, the NTIA must award grants to private sector entities based in the United States to participate in eligible standards-setting bodies (e.g., the Telecommunications Industry Association).