Preheat oven to 350 degrees F.
In a medium bowl, combine chicken, egg, onion, garlic, Italian seasoning, salt and pepper.
Stir to combine.
Place mixture into muffin pan, filling each cup about 3/4 full.
Place one chunk of mozzarella cheese into each muffin cup.
Press cheese into mixture, making sure it is completely covered.
In a small bowl combine Panko, parmesan, parsley and melted butter.
Stir until combined.
Spoon about two tablespoons of crumbs on top of each meatloaf.
Bake for 20 minutes or until chicken is cooked through.
Remove pan from oven.
In a small baking dish, pour 1 cup of spaghetti sauce and spread around so the bottom is evenly coated.
Place meatloaves on top of the sauce.
Spoon 1-2 tablespoons of sauce on top of each meatloaf.
Place on slice of mozzarella on top of each meatloaf.
Place baking dish under preheated broiler and broil until cheese is melted and sauce is heated through.