Step 1: Add the chicken to the slow cooker - Place the boneless skinless chicken breasts directly into the bottom of your slow cooker. Spread them out slightly so they cook evenly.
Step 2: Add the sauce ingredients - Pour the enchilada sauce over the chicken, then sprinkle in the taco seasoning. Add the chopped scallions, minced garlic, fire roasted diced tomatoes, and green chiles.
Step 3: Stir and cook - Give everything a gentle stir just to combine the ingredients. Cover and cook on low for 6 hours or on high for 4 hours until the chicken is fully cooked and tender.
Step 4: Shred the chicken - About 30 minutes before serving, carefully remove the chicken from the slow cooker. Shred it using two forks until it is nice and tender.
Step 5: Add the cheeses - Add the softened cream cheese and 1 cup of the shredded cheddar cheese to the slow cooker. Stir until the cheeses are melted and the sauce is smooth and creamy.
Step 6: Return the chicken - Add the shredded chicken back into the slow cooker. Cover and let it cook for another 15 minutes so everything warms through.
Step 7: Add the pasta - Stir the cooked and drained cavatappi pasta into the slow cooker until fully coated in the cheesy sauce.
Step 8: Finish and serve - Sprinkle the remaining cup of shredded cheddar cheese over the top. Garnish with your favorite toppings and serve warm.