Boil chicken, If I am using boneless chicken I boil it in chicken broth so the broth taste better. Once the chicken is done, remove it from the water, but reserve the broth to mix with the rice. Debone the chicken into bite size pieces and set aside
Cook rice according to the package direction. Instead of water use the chicken broth to cook the rice. Right before the rice is finished cooking add the tomatoes, corn, and mushrooms. Let everything cook for 5 - 10 minutes then add the cheese.
Pour the rice mixture into a casserole pan. Sprinkle the chicken over the rice mixture. Mix the cream of mushroom soup with a little milk or water to thin it out. I usually use less than 1/2 a can of water and then pour the thinned soup over the rice and chicken mixture. Bake at 350 for 30 to 40 minutes.