In this sentence, the phrase “To win a prize” acts as the subject of the verb ‘is’. Since it performs the function of a noun, it is a Noun Phrase.

১. Adjective phrases modify nouns, but here the whole phrase is the subject itself.
২. Adverb phrases describe verbs, but this phrase identifies the ‘what’ of the ambition.
৩. Any group of words acting as a subject or object in a sentence is typically a noun phrase.

অতিরিক্ত তথ্য: Infinitive phrases can often function as noun phrases in English grammar.