Prepare the rice and keep warm. Grill (or broil) the chicken breasts over medium heat, until tender and no longer pink. Shred the chicken with two forks and season with salt and pepper.
To assemble burritos, divide the chicken among the tortillas. Add a scoop of rice and a scoop of beans to each one. Roll up the burritos and place them in a greased baking dish. Repeat for the remaining tortillas. Pour the sauce over the burritos and then sprinkle the cheese on top.
Bake at 375 degrees for 20-30 minutes or until the cheese is melted and the sauce bubbly.