Preheat the oven to 350℉.
Mix together the chicken, egg, garlic, parmesan cheese, parsley, breadcrumbs, salt, and pepper until just combined.
Form about 8-10 large meatballs with the mixture (can use a large cookie scoop).
In a large oven-safe skillet (preferably cast iron) heat 2 tablespoon olive oil on medium heat. Sear all sides of the meatballs for about 2-3 minutes per side.
To the skillet with the meatballs carefully add the marinara sauce.
Sprinkle the shredded mozzarella evenly over top of the sauce and meatballs.
Put the skillet right into the oven and bake at 350℉ for about 10 minutes until the cheese melts and the chicken is cooked to 165℉. Top with fresh parsley.