I need to identify the nouns in this sentence.

One exhibit features the collarless jacket that Lennon wore while performing with the Beatles.

I think there are 4 nouns... exhibit, jacket, Lennon, and Beatles...
what about performing

You're right.

Performing is a gerund and thus can be considered a noun.

thanks :)

You're welcome.

You're correct that "exhibit," "jacket," "Lennon," and "Beatles" are nouns in the sentence. They are all people, places, things, or ideas that the sentence is talking about.

As for "performing," it is actually a verb in this sentence. It describes the action that Lennon was doing while wearing the jacket. Verbs are usually identified as words that express actions or states of being. In this case, "performing" is the action that Lennon was doing.