- 2 (10.5 ounce) cans cream of chicken soup
- 3 cups chopped cooked chicken, or more to taste
- 1 cup finely chopped celery
- 1 cup cornflakes cereal
- 1 (8 ounce) can sliced water chestnuts, drained
- 1/2 cup mayonnaise
- 1/2 cup finely chopped onion
- 1 cup cornflakes cereal
- 2 tablespoons butter, melted, or as needed
- Preheat oven to 350 degrees F (175 degrees C).
- Mix cream of chicken soup, cooked chicken, celery, 1 cup cornflakes, water chestnuts, mayonnaise, and onion together in a large bowl; spread mixture into a 9×13-inch casserole dish.
- Mix 1 cup cornflakes and melted butter together in a bowl until coated; sprinkle over casserole.
- Bake in the preheated oven until casserole is bubbling and topping is crisp, about 45 minutes.