hello,
what do u mean by "nios stops" exactly? means what is the message it displays like "leaving target processor paused" or anything like that or there is no message indication and just disappeared????
i dnt think u have a bunch of nested calls but instead,u check ur custom component and if possible,just for a moment and remove it from ur system and try to excecute again and see what happens with ur system
If succeed then u must have some problm in ur custom component only,Check its interface signals with master/slave interface.
Because i think if stack overflow is the cause of an error then it will nt compile in quartus but that depends on ur nios II code length also
So better is first u remove that component and see what happens.
Hope this will shed some light for ur question.