Prepare the Meatball Mixture: In a large bowl, gently mix together the ground chicken, almond flour, two-thirds of the Parmesan cheese, the egg, minced garlic, Italian seasoning, salt, and pepper. Use your hands to combine everything thoroughly, but be careful not to overmix, which can make the meatballs tough.
Shape the Meatballs: Keep a small bowl of water nearby to moisten your hands as you work. Roll the chicken mixture into about 30-36 evenly sized 1.5-inch balls. Place them on a tray lined with wax paper and refrigerate for 30 minutes to help them firm up.
Brown the Meatballs: Preheat your oven to 375°F (190°C). Heat 1 tablespoon of olive oil in a large oven-safe skillet over medium heat. Add half of the meatballs and brown them on all sides until golden (they don't need to be fully cooked through yet). Transfer them to a plate. Repeat with the remaining olive oil and the rest of the meatballs. Once all are browned, return all the meatballs to the skillet in a single layer.
Add Sauce and Cheese: Spoon your low-carb tomato sauce evenly over the browned meatballs. Then, sprinkle generously with the shredded mozzarella and the remaining Parmesan cheese.
Bake to Perfection: Place the skillet in the preheated oven and bake for 25 to 30 minutes, or until the cheese is wonderfully melted and bubbly, and the sauce is simmering.
Garnish and Serve: Carefully remove the skillet from the oven. Sprinkle with fresh chopped parsley or basil for a burst of fresh flavor.