Prepare the Chicken and Base
Start by placing your boneless, skinless chicken breasts into the bottom of the crockpot. Sprinkle seasoned salt, garlic powder, onion powder, and black pepper evenly over the top. This creates the base flavor that will infuse your chicken as it cooks low and slow. No need to sear or brown anything—let the crockpot do all the work.
Next, pour the cream of mushroom soup, cream of chicken soup, and the full can of diced tomatoes and green chilies over the seasoned chicken. You don’t need to stir—just make sure everything is layered evenly. The liquid from the soups and tomatoes will help steam and cook the chicken perfectly.
Cover the crockpot with its lid and set it to cook on low for about 4 hours. If you’re using chicken thighs, they may need a little less time. Resist the urge to peek or stir too often—the less heat you lose, the more consistent your cooking will be.
Shred Chicken and Add Cheese
Once the chicken is fully cooked and fork-tender, carefully remove it from the crockpot and shred it using two forks or a pair of tongs. It should fall apart easily with no resistance. Return the shredded chicken to the pot and stir it into the creamy mixture.
Now it’s time for the cheese. Add the cubed Velveeta directly to the mixture in the crockpot. It’ll melt slowly, so stir occasionally to make sure it blends evenly into the sauce. If you want to get creative, this is also the moment to add your veggies or spice enhancements.
Let it cook for another 30 minutes on low, uncovered if you want the sauce to thicken slightly. If you’re short on time, you can crank it to high and melt the cheese a bit faster, but be careful not to overcook the sauce.
Cook and Combine Spaghetti
While the cheese is melting in the crockpot, bring a pot of salted water to a boil and cook your spaghetti noodles until just al dente. This usually takes about 8 minutes. Don’t overcook—remember they’ll cook slightly more once mixed into the hot cheese sauce.
Once cooked, drain the noodles well and immediately stir them into the crockpot with the chicken and sauce. Mix thoroughly so the sauce coats every strand of pasta. Taste and adjust seasoning with additional salt and pepper if needed.
Let it all sit together for 5–10 minutes before serving. This gives the flavors a chance to marry and the sauce to settle into the pasta beautifully.