Melt butter in skillet. Cook chicken breasts until mostly cooked.
In a large measuring cup (1 quart), mix onion soup mix, spices (feel free to sub whatever spices/seasoning and amounts that you want.) and can of cream of mushroom soup. Fill measuring cup with water to the 1 quart (4 cup) line.
In large casserole dish, add rice and carrots. Add partly cooked chicken on top of rice and carrots. Pour soup mixture over chicken and rice.
Cover casserole with aluminium foil.
Cook for 45 minutes, or until rice has absorbed almost all of the liquid.