Is the predicate nominative a noun or pronoun?

Either, but if you need to pick one it would be noun.

Explanation:

The predicate nominative (or predicate noun) is the noun or pronoun that comes after a linking verb. It renames the subject of the sentence. The sentence should still make sense if you switch the predicate nominative and the subject.

coin toss of the tosses to the toss

kenny´s more than 25 years of relevant public service. in the army for two decades, as official representative for four years, and now for the department of state, as ambassador. this career clearly demonstrates great capacities in the public sector.