Definition 1 of 2
The nominative case identifies who or what performs the action in a sentence.
In 'She sings beautifully', 'She' is nominative.
Nominative isn't used for the object receiving an action, that's the objective case.
In 'The cat follows her', 'her' is not nominative.
Nominative pronouns include I, you, he, she, it, we, they.
'We will go to the park', 'we' is a nominative pronoun.