Phase 1: Slow Cooking the Chicken and Sauce

1. Prepare the Crock Pot: Lightly grease the inside of a 6-quart or larger slow cooker with cooking spray or butter. This is a crucial step to prevent the cheese from sticking and making cleanup a breeze.
2. Layer the Ingredients: Place the boneless, skinless chicken breasts in a single layer at the bottom of the prepared slow cooker.
3. Create the Sauce: In a large mixing bowl, combine the undiluted cream of chicken soup, cream of mushroom soup, the entire can of diced tomatoes and green chilies (do not drain!), onion powder, garlic powder, dried parsley, salt, and pepper. Whisk everything together until it’s relatively smooth.
4. Add the Cheese and Broth: Add the cubed process cheese (Velveeta) and the ½ cup of chicken broth to the soup mixture. Stir to combine. The mixture will be very thick and lumpy from the cheese cubes, which is perfectly normal.
5. Pour Over Chicken: Pour the entire sauce mixture evenly over the chicken breasts in the slow cooker. Use a spatula to spread it out, ensuring the chicken is fully submerged.
6. Cook: Place the lid on the slow cooker. Cook on LOW for 6-8 hours or on HIGH for 3-4 hours. The ideal setting is LOW, as it allows the chicken to become exceptionally tender and the flavors to meld together beautifully. You’ll know it’s ready when the chicken is fully cooked through and can be easily shredded with a fork.

Phase 2: Final Assembly

1. Cook the Spaghetti: About 30 minutes before the slow cooker is finished, cook the spaghetti according to the package directions in a large pot of salted water. It’s very important to cook the pasta to al dente (still firm to the bite), as it will continue to soften slightly when mixed into the hot sauce. Once cooked, drain the spaghetti thoroughly but do not rinse it.
2. Shred the Chicken: Once the cooking time is complete, carefully remove the chicken breasts from the slow cooker and place them on a cutting board or in a large bowl. The chicken should be incredibly tender. Use two forks to shred the chicken into bite-sized pieces.
3. Finalize the Sauce: The cheese in the slow cooker should be fully melted. Whisk the sauce vigorously until it is smooth, creamy, and homogenous. This step is key to achieving that velvety texture.
4. Combine Everything: Return the shredded chicken to the sauce in the slow cooker. Add the drained, al dente spaghetti and 1 cup of the shredded sharp cheddar cheese. Using a large spoon or tongs, gently stir everything together until the pasta and chicken are completely coated in the creamy sauce and the cheddar cheese is melted and incorporated.
5. Melt and Serve: Sprinkle the remaining 1 cup of shredded cheddar cheese over the top of the spaghetti mixture. Place the lid back on the slow cooker for another 10-15 minutes, or until the cheese on top is fully melted and bubbly.
6. Garnish and Serve: Turn off the slow cooker. Garnish with fresh chopped parsley for a pop of color and freshness before serving hot.