A health care worker certificate from an authorised credentialing organisation, required by federal regulation for certain foreign health care workers including registered nurses.
The certificate is a legal precondition, not a hospital formality
Federal regulation requires listed categories of foreign health care worker to present a certificate before admission, and registered nurses are within the list. The certificate is issued by an independent credentialing organisation and it evaluates the applicant's education against American standards, confirms licensure in good standing, confirms the required examination results and assesses English language ability where that is not otherwise satisfied. Because it depends on documents sent directly by schools and regulators, it is slow, and it is entirely outside the employer's control.
Two practical points follow. First, start it in parallel with the state licence application rather than sequentially, since both need the same underlying verifications. Second, check the current list of covered occupations at the regulation itself, because it extends beyond nursing to several other health professions and the answer differs by occupation.