All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
The children of the sister, whether males or females, are not inheritors at all. Rather, they are relatives who do not inherit their maternal aunt.
So the wealth of the deceased should not be given to them as long as she has an heir; the heirs among men are fifteen and among the women are ten.
You can specify to us the heirs who are alive at the time of her death among the men and the women.
If we presume that she did not have any heirs at all; neither those who have a specific share in the inheritance nor relatives who are entitled to take from the inheritance after those who have specified shares have taken their shares, then the inheritance should be divided between the relatives. If there is no one of them except sons and daughters of the sisters [nieces and nephews], then the entire inheritance is for them.
However, we cannot explain how to divide the inheritance between them until we know whether the sisters are all full-sisters, or half-sisters from the father’s side only, or from the mother’s side only, or that some of them are from the father’s side and some from the mother’s side. It is important to know this before answering, as it has an effect on the answer.
Allah knows best.