Depends on where you are from first of all, which country and where you did your training.
Spain is part of the EU and is under a hiring freeze, so if not from an EU country, it is going to be difficult just to get the basic RN license there.
You will also need to pass the langage exams for licensure there if not from an EU country. You did not specify so I never assume anything.
For any country, it is always basic licensure first, before an advanced practice status.
If you are an American, you may find it easier to get a job with the military there than having to go fhru the licensing process for Spain. With the military, you do not need separate licensure for there and your US licensure is valid for the US military.