In a slow cooker, add the uncooked penne pasta, chicken breasts, salt, black pepper, garlic powder, and Italian seasoning.
Pour the chicken broth over the mixture, ensuring the pasta is submerged.
Cover and cook on low for 4 hours or on high for 2 hours.
After the cooking time, remove the chicken breasts and shred them using two forks. Return the shredded chicken to the slow cooker.
Stir in the heavy cream and grated Parmesan cheese until well combined.
Add the frozen peas and stir gently. Cover and cook for an additional 15 minutes on low until the peas are heated through.
Serve hot, garnished with chopped fresh parsley.