Your husband is great uncle to your niece's son (your great nephew).
Second Cousin
Your grandfather's niece is a first cousin of one of your parents. Her son is your second cousin.
You would be a first cousin by marriage, in other words, there is no direct relationship between you.
Your husband's sister's son is your nephew, just as your sister's son is your nephew.
Your daughter's husband is your son-in-law.
cousin in law.
Your niece's son is your grand-nephew. You are the child's grand aunt, or grand uncle (whichever applies).
Your niece's son's son is her grandson. He is your great great nephew and you are his great great aunt or great great uncle, depending on your gender.
your step son in law it like the same thing as a son in law except its your step daughter's husband.
Great-niece.
She would be his step sister.
Your mother's aunt's husband's sister is your mother's aunts sister-in-law but is not related to you. Her son is not related to you either.