who knows who cares
Probably your niece-in-law.
Your niece's brother is your nephew.
Nothing. Your niece in law. Your brother in laws niece.
Your brother's daughter is your niece. Her daughter is your great niece.
your brother's daughter is you niece
niece/nephew
Great niece
niece
Your husband's niece is your niece, too. You and your husband are her aunt and uncle. Your brother is not related to a niece of yours who is the daughter of your husband's sibling.
Your brother's son or daughter is your nephew or niece respectively.
Your fathers brothers are your uncles. You are their nephew, or niece.
If your niece's is by your sister but the brother is by your sisters new husband & another woman there would be no blood relation. If not then he's the nephew