NSF has a page of guidance and announcements related to the coronavirus at https://www.nsf.gov/news/special_reports/coronavirus/. Note especially that deadlines have been pushed back. The deadline for proposals for NSF-CBMS Summer Research Conferences has been pushed back to June 26, 2020.
See https://www.nsf.gov/bfa/dias/policy/covid19/covid19_deadlines.pdf for the full list of postponements.