• Gather all ingredients.

Prepare the chicken breasts (skip this step if using the breasts from a rotisserie chicken)

• Heat 1 tablespoon of the oil in a large Dutch oven over medium-high heat.
• Season chicken with 1 teaspoon of the Italian seasoning and ¼ teaspoon each of the salt and black pepper.
• Add chicken to Dutch oven; cook, turning once halfway through, until browned, about 6 minutes total (chicken will not be cooked through).
• Remove from the Dutch oven to a plate; set aside. (Do not wipe Dutch oven clean.)

Make the Parmesan Chicken soup (Start with this step if using rotisserie chicken)

• Add the remaining 1 tablespoon of oil and the onion to the Dutch oven; cook over medium-high heat, stirring occasionally, until the onion begins to soften, about 3 minutes.
• Add garlic, crushed red pepper, and remaining 1 teaspoon Italian seasoning; cook, stirring often, until fragrant, about 1 minute.
• Add stock, crushed tomatoes, and chicken breasts; bring to a boil over medium-high heat. 

• Stir in pasta, remaining 1 teaspoon salt, and remaining ¼ teaspoon black pepper.
• Reduce the heat to medium and cook, stirring occasionally, until the pasta is al dente and a thermometer inserted into the thickest portion of the chicken registers 165°F, 10 to 12 minutes.

The finishing touches

• Meanwhile, preheat oven to broil with rack about 6 inches from heat.
• When the chicken is cooked, remove the Dutch oven from the heat.
• Using tongs, transfer chicken to a cutting board.
• Using 2 forks, shred chicken and return to the Dutch oven. Stir in basil until wilted, about 1 minute.
• Ladle soup into 4 broiler-safe bowls, and top each evenly with 5 tablespoons of mozzarella and 1 tablespoon of Parmesan.
• Place bowls on a baking sheet. 
Broil until cheese is melted and browned in spots, 3 to 4 minutes.
• Garnish evenly with additional basil. And if you like it spicy, add an additional sprinkle of red pepper flakes.