In a medium saucepan, bring the water to a boil. Mix in the instant rice, cover, and remove from heat. Let stand 5 minutes.
In a 9x13 inch baking dish, mix the prepared rice, chicken, cream of mushroom soup, cream of chicken soup, butter, milk, broccoli, onion, and processed cheese.
Bake in the preheated oven for 30 to 35 minutes, or until cheese is melted. Stir halfway through cooking to help cheese melt evenly.
