Heat the olive oil in the soup pot over medium heat. Add the diced onion and sauté for 3–4 minutes until translucent.

Add the minced garlic and cook for 30 seconds until fragrant.

Add the diced chicken breasts, salt, pepper, Italian seasoning, dried basil, and red pepper flakes. Sauté for 5–6 minutes, stirring occasionally, until the chicken is mostly cooked through.

Pour in the crushed tomatoes and chicken broth. Stir well and bring the soup to a boil.

Reduce the heat to low, cover, and simmer for 10 minutes.

Add the pasta to the simmering soup. Cook uncovered, stirring occasionally, for 8–10 minutes or until the pasta is al dente and the chicken is cooked through.

Stir in the grated Parmesan and half of the shredded mozzarella until melted and blended.

Ladle the soup into bowls, then top each serving with some of the remaining mozzarella and a sprinkle of chopped fresh parsley or basil. Serve immediately.