Unforgettable Chicken Casserole

3 c. chopped cooked chicken
1 c. sour cream
2 c. finely chopped celery
1 c. mayonnaise
1 c. (4 oz.) shredded Cheddar cheese
1 (4 oz.) can water chestnuts drained, chopped
1 (10 3/4 oz.) can cream of chicken soup
1/2 c. slivered almonds
1 (6 oz.) can French-fried onion rings

In large bowl stir together chicken, celery, cheese, sour cream, mayonnaise, water chestnuts, soup and almonds. Spoon into 9-inch by 13-inch baking dish coated with cooking spray. Bake, uncovered, for 30 minutes in preheated 350° oven. Sprinkle onion rings evenly over top and bake five more minutes or until bubbly around edges. Let stand five-10 minutes before serving. Serves eight.