Begin by cutting the chicken breasts into bite-sized pieces. Season with salt, pepper, and Italian seasoning.
In a large pot or Dutch oven, heat the olive oil over medium heat. Add the chicken pieces and cook until browned and cooked through, about 5-7 minutes. Remove the chicken and set aside.
In the same pot, add the minced garlic and red pepper flakes (if using). Sauté for about 1 minute until fragrant.
Add the chicken broth and crushed tomatoes to the pot, stirring to combine. Bring the mixture to a simmer.
Add the penne pasta and cooked chicken back into the pot. Stir well to coat the pasta. Cover and cook for about 12-15 minutes, or until the pasta is tender, stirring occasionally to prevent sticking.
Once the pasta is cooked, remove from heat. Stir in the grated Parmesan cheese and half of the mozzarella cheese until melted and combined.
Serve the pasta in bowls, topped with the remaining mozzarella cheese and fresh basil leaves, if desired.
Feel free to add vegetables like spinach or bell peppers for extra nutrition.