When a personal pronoun is used as the subject of sentence it in nominative case?

That's correct! When a personal pronoun is used as the subject of a sentence, it is in the nominative case.

Here's a breakdown:

* Subject: The person or thing performing the action of the verb.

* Nominative Case: The form of a pronoun used when it's the subject of a sentence.

Examples:

* I went to the store. ("I" is the subject and in the nominative case)

* She loves to read. ("She" is the subject and in the nominative case)

* They are going to the beach. ("They" is the subject and in the nominative case)

Let me know if you'd like to explore other pronoun cases!