In a large bowl, mix together the chicken, egg, parmesan cheese, 1/2 cup breadcrumbs, garlic powder, and italian seasonings. Roll into 1½ inch balls. Insert a small mozzarella ball in the center of each meatball, reshape the meatball around the cheese, making surethe cheese is completely covered and not exposed. Roll the meatballs in remaining panko breadcrumbs and set aside.
Heat 2 tablespoons of oil in a dutch oven or large oven-safe skillet over medium heat. Working in batches, add the meatballs and brown on each side. Remove from the pan and transfer to a large plate or sheet on.
Wipe out any breadcrumbs from pan and heat the remaining 2 tablespoons of oil over medium heat. Brown the remaining meatballs on each side. Remove from pan.
Preheat oven to 350 degrees.
Wipe clean the same pan used for the meatballs and pour all of the marinara sauce in the pan; add the meatballs and nestle in the sauce. Bake meatballs for 20 minutes sprinkling the mozzarella on top for the last 5 minutes of baking. Garnish with basil and serve over pasta or with crusty bread.