Begin by preparing the meatballs. Add the ground chicken, 1 tablespoon olive oil, egg, parmesan cheese, mozzarella cheese, bread crumbs, Italian seasoning, and salt to a bowl. Gently combine the ingredients with a wooden spoon.

Scoop about 1.5 tablespoons of the meat mixture into your hands and form a ball in between your hands. Set on a plate. Repeat until all of the meatballs have been made, about 18.

Heat the remaining olive oil in a large skillet over medium/high heat. When the oil is hot, add the meatballs to the skillet and cook on all sides until brown. Do not cook the meatballs fully, this will happen later. Remove the meatballs from the skillet.

Add the onion to the pan and season with a pinch of salt. Saute for 2-3 minutes. Add the garlic and saute for an additional 2 minutes or when the garlic is fragrant.

Deglaze the same pan with the red wine. Scrape the brown bits from the bottom of the pan with a spatula.

Add the Italian seasoning, tomato sauce, diced tomatoes, balsamic vinegar, and the remaining salt. Stir and bring to a gentle simmer.

Transfer the meatballs back to the pan into the simmering sauce. Be sure the meatballs are coated in sauce. Simmer over low heat for 5-10 minutes or until the internal temperature of the meatballs reaches 165ºF.

Turn the oven to broil and prepare the topping. Add the mozzarella, panko bread crumbs, and Italian seasoning to a bowl and mix.

When the meatballs are cooking, remove them from the heat and top with the cheese mixture. Transfer to the oven and broil for 2-4 minutes (depending on the oven), and broil until golden brown.

Remove the meatballs from the oven and serve as is, with crostini, or over pasta.