Combine breadcrumbs and parmesan cheese in a bowl. Melt the butter in another bowl. Lightly brush the butter onto the chicken, then dip into breadcrumb mixture. Place on baking sheet and repeat with the remaining chicken.
Lightly spray a little more oil on top and bake in the oven for 25 minutes.
Remove from oven, spoon 1 tbsp sauce over each piece of chicken and top each with 1 1/2 tbsp of shredded mozzarella cheese.