Cook the Rice-a-Roni according to package directions adding an extra 1/2 cup of water. After 5 minutes of cooking add in the carrots, green pepper and onion. Continue cooking for 10 more minutes until rice is cooked and liquid is absorbed.
While the rice is cooking, preheat the oven to 350 degrees and spray a 9x13 baking dish with non-stick cooking spray.
Once the rice is cooked, mix in the cream soup, sour cream, chicken breast. Remove from heat.
Spread the rice mixture evenly in the prepared baking dish. Sprinkle with the shredded cheese.
Bake uncovered at 350 degrees for 30 minutes. Serve 6.