If making homemade chicken meatballs, combine ground chicken, panko breadcrumbs, egg, garlic, Italian seasoning, red pepper flakes, salt, and 1 tbsp olive oil in a large bowl. Mix until just combined, then roll into 24 meatballs about 1 inch in size. Do not overwork the mixture.

Heat 2 tbsp olive oil in a large skillet over medium-high heat. Once the oil shimmers, add the chicken meatballs in a single layer. Turn gently every minute or so for 4 to 5 minutes until golden brown on all sides.

Reduce heat to low, slowly add the marinara sauce, then increase to medium-low. Cover and cook for 12 to 15 minutes or until the internal temperature reaches 165 degrees F.

If using frozen chicken meatballs, heat marinara sauce over medium heat until simmering. Add frozen meatballs, cover, reduce to medium-low, and cook for 20 to 25 minutes until the internal temperature reaches 165 degrees F.

While the chicken meatballs finish cooking, place the hot dog buns open-side-up on a baking sheet. Move the top oven rack to 6 inches below the broiler and preheat the broiler on high.

Add 3 chicken meatballs to each bun. Spoon marinara sauce over the top and sprinkle with shredded mozzarella. Broil for 2 to 3 minutes until the cheese is melted and bubbly. Watch closely to prevent the buns from burning.