Begin by placing the boneless, skinless chicken breasts at the bottom of your slow cooker. Season them generously with salt, pepper, garlic powder, and Italian seasoning for a savory flavor.

In a medium bowl, whisk together the cream of chicken soup and chicken broth until smooth. Pour this creamy mixture over the seasoned chicken, making sure it's evenly covered.

Gently add the diced tomatoes and penne pasta into the slow cooker, ensuring they sit on top of the chicken and soup mixture. Stir delicately to submerge the pasta, allowing it to soak up all that delicious flavor.

Cover the slow cooker and cook on low heat for 4-5 hours, or switch to high for 2-3 hours.

After the cooking period, carefully remove the chicken breasts using tongs. Shred them into bite-sized pieces with two forks and return the juicy chicken back to the slow cooker.

Stir in the shredded cheddar and mozzarella cheese until everything is melted and creamy. Taste and adjust the seasoning with more salt and pepper if needed.

Dish out the Slow Cooker Cheesy Chicken Penne while it's hot, and finish each serving with a sprinkle of freshly chopped parsley for a pop of color and freshness.