Place the chicken breasts in the bottom of the Crock Pot. Sprinkle the Cajun seasoning, garlic powder, onion powder, black pepper, and salt evenly over the chicken.
Pour the cream of chicken soup, diced tomatoes (with their juice), and chicken broth over the seasoned chicken. Stir gently to combine.
Cover and cook on low for 6 hours or on high for 3 hours, until the chicken is cooked through and tender.
Remove the chicken from the Crock Pot and shred it using two forks. Return the shredded chicken to the pot.
Stir in the heavy cream and uncooked penne pasta. Cover and cook on high for an additional 30 minutes, or until the pasta is cooked al dente.
Once the pasta is cooked, stir in the mozzarella cheese until melted and creamy.
Serve hot, garnished with chopped parsley.