Preheat oven to 350 degrees. Spray a 9 x 13 inch baking dish with non-stick cooking spray.
Add ranch dressing mixcrushed corn flakes, and parmesan cheese to a gallon sized freezer bag. Dip each of the chicken breasts in the melted butter. Add the chicken breasts to the bag of coating one at a time. Shake to coat the chicken each time and then place each chicken breasts in the baking pan.
Sprinkle any of the remaining coating over the chicken breats in the dish.
Bake chicken at 375 degrees for 40 minutescheck at 25 minutes to make sure coating isn't getting too brown. If needed cover with foil at that point to prevent the coating from burning. Serves 4.