Start by gathering all your ingredients. Mince the garlic and chop the sun-dried tomatoes if they are not already chopped.
In your crockpot, add the crushed tomatoes, Italian seasoning, minced garlic, and the jar of sun-dried tomatoes (with their oil). Stir everything together to combine.
Place the boneless skinless chicken breasts on top of the mixture and season with a pinch of salt and pepper.
Pour the jar of alfredo sauce over the chicken and tomato mixture, mixing gently to ensure the chicken is coated.
Cover the crockpot and cook on low for about 6 to 8 hours or on high for 3 to 4 hours.
Once cooked, remove the chicken and shred it with two forks, then return it to the crockpot and stir.
Prepare the fettuccine noodles according to package instructions, then drain.
Stir the cooked fettuccine into the crockpot and mix until well coated. Top with grated parmesan cheese before serving!