This kid won't knock it off and he's on my last nerve. I think I should tell my 10 year old nephew that he's really annoying.
That's a harsh thing to say to a kid. How will that affect your relationship with your nephew?
He'll probably be mad at me but he has to improve his behavior.
I'm sure you're nephew's behavior is frustrating to you and it's fine to tell him that he's annoying you. Children should not misbehave around adults and their behavior should be corrected when necessary.
Well my nephew won't stop asking me for things, he's constantly texting me and he's getting annoying.
It sounds like he's just trying to be close to you. Try not to think of it as annoying, but as a change to strengthen your relationship with him.