Chicken, Green Bean and Rice Casserole

Mom always made this for us when we were growing up.  I can still remember it now.  In fact, I was so excited when someone from church made this casserole for us after The Bun was born.  It brought back such good memories of home for this overwhelmed Mama.  I always despised the water chestnuts in it while I was growing up, but found myself enjoying the crunch when we had it last year.  The difference was having whole chestnuts growing up and having them chopped later.  I was having some company over after church one Sunday and this is what I served.  Along with the Pecan Pie and Fancy Salad.  I'm going to give the whole recipe, but of course, omit things you don't prefer.

Chicken, Green Bean and Rice Casserole

3 c. cooked and diced chicken
1 onion, diced and sauteed
2 (14.5 oz.) cans French green beans, drained
1 can cream of celery soup
1 c. mayo
1 (6 oz.) box long grain and wild rice, cooked according to package directions
1 c. grated cheddar cheese
1 (8 oz.) can water chestnuts, drained and chopped (optional)
1 (4 oz.) can pimentos, drained (optional)
1 can french fried onion rings (optional)

Preheat oven to 300 degrees.  Mix all ingredients except onion rings together and pour into 3 quart casserole.  Bake for 25 minutes.  Add onion rings on top and continue baking until browned.