No not confirmed that i can remember. Is it confirmed that seswatha is Nau-Cayuti daddy
It's never confirmed or denied, it's a possibility that is brought up by Akka's dreams in TJE.
In fact, if I remember correctly, Akka ponders on how Kellhus resembles both Celmomas and Nau-Cayûti in two separate occasions during PON (coming shortly after dreams of Celmomas' death and Seswatha and Nau-Cayûti in Golgotterath). That, to me, lends credence to the idea that Celmomas
was Nau-Cayûti's father after all, since there appears to be a strong resemblance between the two (no resemblance between Seswatha and Nau-Cayûti is ever noted - not that it definitely proves anything, anyway).