Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
In a large mixing bowl, combine the ground chicken, breadcrumbs, grated Parmesan, parsley, egg, minced garlic, onion powder, Italian seasoning, salt, and pepper. Mix until well combined but do not overwork the meat.
Using your hands, form the mixture into meatballs, about 1.5 inches in diameter, and place them on the prepared baking sheet.
Bake the meatballs in the preheated oven for 20 minutes or until they are cooked through and golden brown on the outside.
While the meatballs are baking, heat the marinara sauce in a saucepan over medium heat until warmed through.
Once the meatballs are done baking, remove them from the oven and carefully place them into the marinara sauce. Gently spoon some sauce over each meatball.
Sprinkle the shredded mozzarella evenly over the meatballs and allow it to melt in the sauce, either by covering and simmering on low for about 5 minutes or by placing the skillet in the oven for an additional 5 minutes until the cheese is bubbly.
Serve hot, garnished with fresh basil leaves on top for added flavor and color.
Notes
For extra flavor, use freshly grated cheese and homemade marinara sauce if possible.