Like Nuka said, they ran off.

i bet they were exiled

Nuka was probably referring to hyenas with no name.

But why? I mean, it was one less lion to share space with.

they probably just ran away, died, got eaten, were chased
away. who knows. i think it's better off without them. they
were so annoying. but that's my opinnion. we won't know what
happened to them really.
then again, they could've
went bak to timon's old home or somewhere similar to find
meerkats to chase, kill, play with.

i agree with Sarabi Fan.... but one thing i think
different is that i don't believe all of hyeenas jumped on
Scar when the Pride Lands caught on fire... they might have
just died or was taken out of the movie so when the people
made LK2 they probably already had the plot about the
Outsiders....if the hyeenas were in the LK2 what would
really be the point of the Outsiders?!

Actually, when nuka mentions them, 'this place is dead ever
since the hyenas ran off.' that kind of answers the
question, They ran off,

When the fire raged up,they jumped onto Scar,perhaps they
died along with him.

All Nuka said was that They ran off.

i am not sure about this but i think they moved on to a
different land because of Simba coming home. hope that makes
sence and answers your question!