Place the raw chicken breasts at the bottom of the slow cooker. Ensure they are laid out in an even layer so they cook through at the same rate. Season the chicken with garlic powder, black pepper, and dried sage.
Pour the entire bottle of garlic parmesan wing sauce over the chicken. Place the cubes of softened cream cheese on top. This will melt down during the cooking process to create the base of your creamy sauce.
Cover the crockpot with the lid and set it to cook on Low for 4 to 6 hours, or on High for 2 to 3 hours. You will know the chicken is ready when it is tender enough to be easily shredded with two forks.
Once the cook time is complete, use two forks to shred the chicken directly in the pot. Stir the shredded chicken into the sauce and melted cream cheese until everything is well combined and smooth.
While the chicken is being shredded, cook your pasta on the stove according to the package directions. Aim for “al dente” texture, as the pasta will soften slightly more when added to the crockpot. Drain the pasta well.
Add the cooked pasta, heavy cream, milk, and grated parmesan cheese to the slow cooker. Stir everything together until the pasta is fully coated in the creamy sauce. Cover and let it sit for another 10-15 minutes on the “Warm” setting to allow the sauce to thicken before serving.