Spray the inside of a 6 quart crockpot with non-stick cooking spray. Cut boneless, skinless chicken breasts into 3-4 strips. Place strips into prepared crockpot.
Pour melted butter over chicken. sprinkle Italian dressing mix all over chicken, minced onion, salt & pepper, minced garlic, cream of soup, & chicken broth. Mix ingredients all together with chicken. Make sure chicken is submerged in the mixture.
Place sliced cream cheese over the chicken & mixture. Do not stir in.
Place lid on crockpot and cook on high for 2 - 3 hours or on low for 4- 6 hours or until chicken is cooked through and fork tender.NOTE: cook time will depend on how big your chicken is in the crockpot. Once chicken is fork tender, you can shred chicken with 2 forks, a meat chopper, or cut your chicken on a cutting board into bite size pieces & place back into crockpot.
Stir in mozzarella cheese, parmesan cheese, and dried parsley.
Cook fettuccini in a large pot of boiling water with 1/2 TBS salt per directions on back of package for al dente. Drain pasta and add to crockpot with chicken and and sauce. Mix well to combine. Serve it up.