Preheat oven to 350 degrees. Place chickenin a 9 by 13 inch baking pan. Drizzle 1 tablespoon butter over each chickenpiece. Sprinkle dry onion soup mix evenly over chicken breasts. Place onions and potatoes in pan around chicken.
Cover pan with lid or foil and bake for 50 minutes. Uncover and continue baking for 10-15 minutes more until chicken and potatoes are done and browned a bit.