Games that don't use exceptions tend to do so because of performance concerns. Nethack is a turn-based game, so performance isn't as relevant here.
Re:Memory management in C programs (2014)
by AbacusAvenger on Monday July 18, 2016 @11:10PM
(#12119305)
Bear in mind this is Nethack4 which is a fork of Nethack.
In games, you have a small number of functions that can tolerate failure, probably relating to IO. Everything else instantly explodes.