Who inherits from a woman who is Kalalah, having neither children nor sisters, but has nieces (daughters of sisters) and a paternal grandnephew (son of a son of a brother)? Do they inherit anything or not?

The sister's children are not among the heirs. As for the son of the brother's son, if he is a full brother or a paternal brother, he is among the heirs. But if he is a maternal brother, his children are not among the heirs.