In a large mixing bowl, combine ground chicken, breadcrumbs, grated Parmesan, egg, minced garlic, Italian seasoning, salt, and pepper. Mix gently without overworking to keep them tender. Shape the mixture into meatballs about 1 inch in diameter. Set aside on a plate as you preheat your skillet.

Heat a tablespoon of olive oil in a large skillet over medium heat. Once hot, carefully add the chicken meatballs, ensuring they are not overcrowded. Brown the meatballs on all sides for about 5-7 minutes until golden and slightly crispy. Remove from the skillet and set aside.

In the same skillet, add diced onion, carrots, celery, and additional minced garlic to the leftover oil. Sauté these vegetables over medium heat for 5-7 minutes until softened and the onion becomes translucent.

Add diced tomatoes, chicken broth, white beans, fresh thyme, and a bay leaf to the softened vegetables in the skillet. Stir to combine, bringing the mixture to a gentle simmer.

Return the browned chicken meatballs to the skillet, gently nestling them into the simmering sauce. Cover and transfer to a preheated oven at 375°F (190°C). Bake for 25-30 minutes.

Once baked, carefully remove the skillet from the oven and discard the bay leaf and thyme stems. Stir the Chicken Meatball Cassoulet gently before serving.