Prepare the slow cooker by coating it with a light layer of cooking spray.
Place the chicken breasts in the slow cooker and season lightly with salt and pepper if desired.
Pour the entire bottle of Garlic Parmesan sauce over the chicken, then top with cubed cream cheese.
Cover and cook on low for 4-6 hours or until the chicken is tender and easily shreddable.
About 15 minutes before serving, cook the rotini pasta according to the package instructions, reserving ½ cup of the pasta water before draining.
Remove the chicken from the slow cooker and shred it. Whisk the cream cheese into the sauce until smooth and fully melted.
Return the shredded chicken to the slow cooker, stirring to coat it in the sauce.
Stir in the cooked pasta, adding reserved pasta water if needed to loosen the sauce.
Serve hot, garnished with shredded parmesan and fresh parsley.