What compact privilege is
A multistate license from your primary state of residence carries compact privilege — the authority to practice in other compact states without licensing separately in each. It only exists between states that are live in the Nurse Licensure Compact.
Why privilege does not reach Puerto Rico
Since Puerto Rico is not part of the compact, there is no Puerto Rico compact privilege to grant. See non-compact states and working in a non-compact state with a compact license.
The law that governs this in Puerto Rico
Working in Puerto Rico on another state’s license is practice in Puerto Rico, so it is Puerto Rico’s own nurse practice act that defines what you may do and the Puerto Rico Board of Nurse Examiners that applies it. That act is Ley para Regular la Práctica de la Enfermería en Puerto Rico, 20 L.P.R.A. ch. 9A (board powers at § 204f).
There is no compact statute to cite for Puerto Rico, which is the substantive point rather than a gap in our research: Puerto Rico has not adopted the compact, so the practice act above is the whole of the law that applies to you here.
Confirm before you rely on it
License status changes and the compact evolves. Confirm your own license type on Nursys and check Puerto Rico’s current rules with the Puerto Rico Board of Nurse Examiners. CompactStates.com is an independent guide, not a licensing authority.
Why compact privilege does not reach Puerto Rico
Puerto Rico has not adopted the compact. Either way the practical answer for working in Puerto Rico on a license from another state is the same today: a multistate license from another state does not authorize it, and you generally need a Puerto Rico license from the Puerto Rico Board of Nurse Examiners. Re-check before a start date rather than assuming — this is precisely the fact that changes.