A nephew is offspring of a brother or sister, or one’s brother/sister’s children. In other words, nephew refers to a male offspring that is linked to you by ties of the siblingship. The term “nephew” is understood to be a young man, a relative, who is junior to one, or younger than one is. Nephews are also part of a person’s family and it is usually common to hear people have special feelings for nephews especially to their uncles or aunties.

Nephew is a part of speech known as a nominals since it represents a conception of a human person a place thing or idea. Here are some examples of how "nephew" can be used as a noun in sentences:Here are some examples of how "nephew" can be used as a noun in sentences:
Also I have my nephew who is coming over for the weekend. (subject of the sentence)

Hey can you please come and pick up my nephew after school today? noun1 (a person, location or thing the action of pick up refers to)
I like to accept that I am proud of him and I give full credit to him. (possessive noun modifying "accomplishments")

My sister’s nephew, for instance, is also my nephew because he is the cousin to my own nephew. [A compound noun referring to a part of an entity incorporated into another entity and forming part of a complex syntactic construction with the other constituent of the compound.]

Noticing the expression on the face of my dear little nephew, I thought he was glad to see me again.As it necessarily implies a preposition, the noun in question is in a prepositional phrase.