Preheat oven to 400 degrees and spread ½ cup of the pasta sauce in the bottom of a cast iron skillet OR square casserole dish. Set aside.
In a large bowl combine chicken, ½ cup breadcrumbs, ¼ cup parmesan cheese, garlic, egg, and salt, mixing with your hands until completely incorporated (will be sticky!)
Divide chicken mixture into 12 equal sections, rolling them into loosely formed meatballs.
In a shallow bowl, add 1 cup breadcrumbs.
Taking each meatball, flatten to a circle and slightly indent the center with your thumb.
Insert a piece of cheese and enclose completely with the chicken mixture (might be easier with damp hands). Roll the formed meatball in the breadcrumbs until coated.
Repeat with all 12 meatballs.
In a lightly oiled skillet over medium high heat, cook meatballs until lightly browned on every side. Then place in the prepared skillet or casserole dish.
Bake for 12-14 minutes.
Remove from oven and cover with remaining 1 cup pasta sauce, remaining 4 ounces of fresh mozzerlla and ¼ cup parmesan.
Return to oven and bake for 10-12 more minutes or until meatballs are completely cooked through.
Broil for a few minutes longer if you desire the cheese to be bubbly and slightly browned.