National Infrastructure Simulation and Analysis Center Pandemic Modeling Act of 2020 This bill expands the authority of the National Infrastructure Simulation and Analysis Center to cover pandemics and other activities deemed appropriate by the Cybersecurity and Infrastructure Security Agency (CISA). It also requires the center to provide modeling, simulation, and analyses to federal agencies upon request and not later than 15 days after completion. The CISA shall provide by October 1, 2021, and annually thereafter, summaries of priorities of the center and of current projects carried out to each federal agency or department with critical infrastructure responsibilities. If such an agency requests additional information on a specific project, the CISA shall provide the information within 30 days after the request. The CISA shall (1) within 45 days after this bill's enactment, provide all pandemic reports of the center completed before enactment to each federal agency with critical infrastructure responsibilities; and (2) by October 1, 2021, and annually thereafter, brief Congress on current pandemic modeling, simulation, and analyses of the center, and how the Department of Homeland Security is applying this information to current and future COVID-19 (i.e., coronavirus disease 2019) pandemic work.