Place the chicken breasts in the slow cooker and season them with salt, pepper, and Italian seasoning.
Add the minced garlic and pour the chicken broth over the chicken. Cover and cook on low for 4-5 hours, or until the chicken is tender and fully cooked.
Once the chicken is cooked, remove it from the slow cooker and shred it using two forks. Return the shredded chicken back to the slow cooker.
Stir in the heavy cream and grated Parmesan cheese until well combined. If you're adding broccoli or spinach, toss it in now.
Add the uncooked fettuccine pasta to the slow cooker, pressing it gently into the sauce. Cover and cook on low for an additional 30-40 minutes, or until the pasta is tender.
Stir the pasta and sauce mixture well to ensure everything is coated. Adjust seasoning with more salt or pepper if needed.
Serve hot, garnished with fresh parsley for a pop of color and flavor.
Notes
Feel free to add vegetables like broccoli or spinach for extra nutrition.