Preparation
Preheat oven to 350 degrees F.
In a mixing bowl mix together mushroom soup with milk and stir until well blended.
Take 1 cup of soup and milk mixture and set aside.
Using the remainder of the soup mixture, add rice and mushrooms.
Pour rice and soup mixture into a 9x13 baking dish.
Place chicken breasts on top of mixture.
Pour the set-aside soup mixture over the chicken.
Cover baking dish with aluminum foil and bake for 1 hour.
Remove foil and bake for an additional 15 minutes.