Boil chicken breast, shred and set to the side.
Boil squash and onions, then drain.
In a big bowl, put squash, onions, chicken, sour cream, soup, and crackers and stir.
Pour in a 9x13 cake pan and bake at 350 for 30 mins.
Remove from oven and sprinkle with cheese.
Return to oven until cheese melts.