In a 4-6 quart slow cooker, spray it with non-stick cooking spray and place the chicken in it. Top the chicken with half of the Alfredo sauce and clove of garlic. {Note - if your sauce is already full of garlic, you can skip the garlic clove.}
Cover and cook on low for 6-8 hours, once the chicken is done, shred it with a fork and mix up the sauce to be sure it's coated.
At this point, you can use all the chicken or you can go with 1 cup of shredded chicken and freeze the rest to use later.
Cook the pasta as instructed on the package.
While it's draining, add the cream cheese, milk, and salt to the saucepan on low-medium heat.
Lightly stir until the cheese is melted and the sauce is formed, add more milk if needed.
Add in the cooked and drained pasta, the remaining Alfredo sauce, and 1 cup of shredded chicken.
Stir and serve with additional cheese and parsley.