Answer:
Abraham Lincoln
Step-by-step explanation:
A predicate noun (also called a predicate nominative) is a noun or a noun phrase that follows a linking verb and renames or identifies the subject of the sentence.
The subject is what the sentence is about. It tells us who/what performs an action expressed by the verb or is being described. In the given sentence, the complete subject is one of the most loved presidents of the United States. The linking verb is is, and the predicate noun is Abraham Lincoln.