Not a lawyer but here is the SEC requirement. Item 8.01 would apply to NRXP or any SEC-regulated company.
Companies have four business days to file a Form 8-K for the events specified in the items in Sections 1-6 and 9 above. However, if the issuer is furnishing a Form 8-K solely to satisfy its obligations under Regulation FD, then the due date might be earlier. https://www.sec.gov/fast-answers/answersform8khtm.html