In a slow cooker, combine the cream of mushroom soup, rotel, cream cheese, velveeta cheese, garlic powder, and onion powder. Stir to mix the ingredients together.
Add the chicken breasts to the slow cooker, nestling them into the mixture. Cover and cook on low for 5-6 hours, or until the chicken is fully cooked and tender.
Once the chicken is cooked, remove it from the slow cooker and shred it using two forks. Return the shredded chicken to the slow cooker and stir to combine.
Cook the spaghetti according to the package instructions. Drain the pasta and add it to the slow cooker. Mix well to coat the spaghetti evenly in the sauce. Add salt and pepper to taste at this point if desired.
Sprinkle the shredded sharp cheddar cheese over the top of the spaghetti mixture. Cover the slow cooker and continue cooking on low for 10-15 minutes, or until the cheese is melted.
Serve the chicken spaghetti warm, garnished with additional shredded cheese or fresh parsley if desired. Enjoy!