-Preheat oven to 350 degrees F (175 degrees C). Spray a 13×9-inch baking dish with cooking spray.
-Spread chicken pieces, broccoli, and potatoes into the prepared baking dish, respectively. Drizzle melted butter over the ingredients in the container and season with the Italian dressing mix.
-Bake in a preheated oven until the chicken is cooked and the potatoes are tender for 45 to 60 minutes.