The daughter of your husband's brother is his (and your) niece. Her daughter is his (and your) great niece.
Its would be your neice
Your brother's daughters are your nieces
Your daughter's husband is your son-in-law.
you call her your daughter's husband's sister
Granddaughter
brother in law
Your grandson.
Well, I call her Abigail, but different strokes, etc.
You call your daughter's baby, your grand-duaghter.
You would call your sister's daughter your niece.
Are you asking what you call your brothers daughter? Well if you are your brothers daughter is called your niece.
They'd be your cousin.