Preheat oven to 375 degrees F. Light spray/grease casserole dish. Mix bread crumbs and 3 cups of cheese together in a shallow bowl or plate. Whisk egg in another shallow bowl or plate. Dip each piece of chicken in egg then breadcrumb and cheese mixture until fully coated.
Roll chicken in a ball and place in casserole dish. Repeat until all chicken is done. Sprinkle remaining cheese on top of all chicken - be generous. Add more cheese if desired. Melt butter and drizzle over chicken and cheese.
Bake for 35-45 minutes or until chicken is cooked through.