Preheat oven to 350° F
Saute celery and onion in 1 tablespoon butter.
Combine chicken, onion, celery, rice, salt, pepper, parsley, soup mix, can soup (undiluted), water chestnuts, and mayonnaise in large bowl and stir to evenly mix.
Pour mixture into 8×8 inch casserole dish, top with corn flakes, then bake for 30 minutes.
While casserole bakes, saute almonds in 1 tablespoon butter until slightly browned. Set aside.
Top casserole with almonds once finished baking, let cool for 10 minutes before serving.
