Karen (Keller) Thomas' Chicken Casserole

4 boneless chicken breasts, sliced up if desired
1 can cream of chicken soup
1 can evaporated milk
8 oz. sour cream
3 c grated cheddar cheese
1 box Ritz crackers, crushed
16 oz. of cooked broccoli or squash or your favorite green vegetable
1 stick of melted butter