Your nephew's son is your great nephew.
You would be his Great Uncle and he would be your Great Nephew.
Your nephew's son is your grand nephew or, some would say, your great nephew. You are his great aunt or great uncle.
your nephews
Great nephew
himselfhis brothershis first cousinsHis cousin in law once removed.
3rd cousin
Second cousins once removed.
It does not appear that Thomas Jefferson had any nieces or nephews. He had a daughter, a son in law and two grandsons. He also had an aunt and a first cousin.
who played four test for india in 1930s and has sons and two nephews who captained pakistan
Sean Anderson, the son of Maxwell Anderson
The sons of your son-in-law's siblings are his nephews. You are not related to them.However, your son-in-law is married to your daughter. The sons of her siblings are also your son-in-law's nephews. They are your grandsons.
The nephews and nieces have equal standing under the law. However, if one wishes to speak of royal precedent, then the deceased's eldest sister's eldest son, and if she had no son, then the eldest son of the oldest sister who did have sons.