Preheat oven to 350°F (175°C).
Place the stick of butter in a 9x13-inch baking dish and melt in the oven while it preheats.
Once the butter is melted, remove the dish from the oven.
Arrange the chicken breasts evenly over the melted butter.
In a mixing bowl, combine the rice, cream of chicken soup, cream of mushroom soup, cream of celery soup, chicken broth, garlic powder, onion powder, salt, and pepper. Mix until well blended.
Pour the mixture evenly over the chicken in the baking dish.
Cover tightly with aluminum foil and bake for 1 hour.
Remove the foil and bake for an additional 20-25 minutes, until the chicken is cooked through and the rice is tender.
Garnish with fresh parsley before serving.