Lightly grease the inside of your slow cooker with non-stick cooking spray.

Place the chicken breasts in the slow cooker.

Add the cream of chicken soup, cream of mushroom soup, Rotel tomatoes (with juices), salt, and pepper.

Cover and cook on low for 6-8 hours or on high for 3-4 hours, until the chicken is fully cooked and tender.

Remove the chicken breasts from the slow cooker and shred them using two forks.

Return the shredded chicken to the slow cooker.

Stir in the cubed cream cheese and 1.5 cups of the shredded cheddar cheese.

Cover and cook on low for an additional 20-30 minutes, stirring occasionally, until the cheeses are melted and the sauce is creamy.

While the cheeses are melting, cook the spaghetti according to the package instructions until al dente. Drain the pasta well.

Add the cooked spaghetti to the slow cooker, gently tossing to coat the pasta evenly with the creamy chicken sauce.

Serve the creamy chicken spaghetti warm, garnished with the remaining shredded cheddar cheese and chopped fresh parsley, if desired.