Heat the Olive Oil: In a large pot or Dutch oven, heat 2 tablespoons of olive oil over medium heat.
Sauté Vegetables: Add 1 small diced onion and sauté for 3-4 minutes until softened. Add 2 minced garlic cloves and 1 diced bell pepper, cooking for another 2-3 minutes until fragrant and the bell pepper is tender.
Cook the Chicken: Add 1 pound of cubed boneless, skinless chicken breasts to the pot. Season with 1 teaspoon of salt and 1/2 teaspoon of black pepper. Cook until the chicken is browned on all sides, about 5–7 minutes.
Add Broth and Tomatoes: Pour in 4 cups of low-sodium chicken broth and add 1 can of diced tomatoes with their juices. Stir to combine.
Season the Soup: Add 1 teaspoon of dried oregano and 1 teaspoon of dried basil to the pot. Stir to incorporate all the flavors.
Bring to a Boil: Increase the heat to high, bringing the soup to a boil. Once boiling, reduce the heat to low and let it simmer for 10 minutes to allow the flavors to meld.
Add the Pasta: Stir in 1 cup of uncooked pasta and cook according to the package instructions until al dente, usually about 7-10 minutes.
Add Cheese: Once the pasta is cooked, turn off the heat and stir in 1 cup of freshly grated Parmesan cheese and 1 cup of shredded mozzarella cheese, allowing it to melt into the warm soup.
Garnish and Serve: Ladle the soup into bowls, garnish with fresh basil leaves, and enjoy the comforting flavors of this Chicken Parmesan Soup!