Cheesy potato casserole

From: Me...
8 to 10 cups frozen shredded potato's
1/2 cup melted butter
1 onion chopped
1 can cream of chicken soup
1 pint of sour cream
2 cups grated cheese
salt & pepper
Saute the onion in the butter, add to this all of the remaining ingredients except potato's.  Spray a 9X13 casserole dish, spread 1/2 of the potato's down then cover with 1/2 of the sauce.  Repeat with remaining potato's and then the rest of the sauce.  Bake uncovered for 35 to 45 minutes at 350 degrees.