Though let's be honest. If the PCs haven't been multiclassing, then by that point a cleric would have True Resurrection which could bring her back... or a Wizard with Wish.
We have no wizard and our cleric is also an oracle. :)
So my thought, and I don't know if anyone else has already mentioned or thought of it, is this: Couldn't Baba Yaga, as part of her wish granting as a thank you/I refuse to owe people, bring back Nadya's daughter?
