Ms. Becky’s Broccoli, Rice Chicken Casserole

2 cups cooked rice
3 chicken breasts, cooked and cubed
1 small cream of celery soup
1 small cream of chicken soup
1/4 cup butter
1 cup milk
1 (16 oz.) package frozen broccoli
1 small white onion, chopped
1 pound processed cheese food
1 cup chopped celery
Directions:
Preheat oven to 350 degrees. Sauté onion and celery in butter until tender. Mix soups and milk over medium heat. Add cheese. Heat until melted. Cook instant rice. Boil chicken and cut into cubes. Spray 13×9 pan with non stick spray. Combine vegetables with soups. Add rice and chicken. Pour into baking pan. Cook for 1 hour.