Wild Chicken and Rice Casserole

5 Cups of cooked chicken, diced (I only used about 3 cups, and chopped in food processor because we like it smooth)
2 Cans Cream of Mushroom soup
1/2 Cup of diced Celery
1/2 Cup diced Onion
3 Cups grated Cheddar Cheese
1 Cup grated Cheddar Cheese
16 oz. Sour Cream
1 Cup Milk
2 Cans of Water Chestnuts (I didn't use these)
2 6 oz. box of Uncle Ben's Long Grain Rice, already cooked.

Saute onion, celery and water chestnuts for 10 minutes. Then mix all ingredients together except for the 1 cup of cheese. Pour into a greased casserole dish. Cook at 350 degrees for 30 minutes then sprinkle the remaining 1 cup of cheese on top and cook 5 more minutes. (from my friend Angel)