Example of predicate nominative

A predicate nominative is the noun or a pronoun following a linking verb that restates or stands for the subject.

A linking verb acts as an equals sign, the object is a form of the subject (Mary is my sister. Mary=sister); or the subject becomes the object (Mary was elected class president. Mary ->class president).

Example:

Baton Rouge is the capital of Louisiana. (Baton Rouge = capital)

Our street was a complete disaster after the storm. (street -> disaster)