Make the Meatball Mixture

1. Combine Ingredients: In a large bowl, mix the ground chicken, breadcrumbs, Parmesan cheese, parsley, milk, egg, garlic, oregano, basil, salt, and pepper.
2. Form the Meatballs: Use your hands to mix the ingredients until well combined. Roll the mixture into 1 1/2-inch meatballs and set them aside on a plate.

Cook the Meatballs

1. Heat Oil: Heat a tablespoon of olive oil in a large skillet over medium heat.
2. Brown the Meatballs: Add the meatballs to the skillet in batches, making sure not to overcrowd the pan. Cook for 5-7 minutes, turning occasionally, until the meatballs are golden brown on all sides.
3. Finish Cooking: Once the meatballs are browned, transfer them to a baking dish and bake in a preheated 375°F (190°C) oven for an additional 10-12 minutes until they are cooked through.

Prepare the Sauce

1. Simmer the Sauce: While the meatballs are baking, heat the marinara sauce in a small saucepan over medium heat. Bring to a simmer and cook for 5 minutes.
2. Add Mozzarella: Once the sauce is warm, stir in the shredded mozzarella cheese and cook for an additional 2-3 minutes, until the cheese is melted and the sauce is bubbly.

Assemble the Dish

1. Top with Sauce: Once the meatballs are done baking, pour the cheesy marinara sauce over the meatballs.
2. Serve: Serve immediately with pasta, garlic bread, or enjoy on their own as an appetizer.