Preheat oven to 350°F. Prepare a baking sheet by lining with parchment paper.
Set aside 1 cup marinara, 1 cup shredded mozzarella cheese and 1/4 cup Parmesan cheese.
In a large mixing bowl, combine all remaining ingredients (chicken, breadcrumbs, 1 cup Parmesan, garlic, onion, 2 tablespoons marinara sauce, Italian seasoning, basil, parsley, salt, pepper and egg). Mix well, do not over mix or you will have tough meatballs.
Using a 1-1/2 tablespoon scoop, portion out meat mixture and place on baking sheet. After all meatballs have been scooped onto tray, roll into balls.
Bake for 16-18 minutes until lightly browned.
Turn oven to broil.
Drizzle a spoonful of marinara over each meatball. Sprinkle with mozzarella cheese.
Broil for 2-3 minutes until cheese is golden brown and bubbly.