Set a skillet over medium heat and add the ground chorizo. Cook 5 to 6 minutes breaking it apart as it cooks. Remove the chorizo and place on a plate lined with paper towels to drain extra grease.

Put the chicken in the slow cooker and season well with kosher salt, pepper, and chili powder.

Add the cooked chorizo, onion, garlic, green chiles, and queso. Add the milk to the empty jar of queso, put the lid on and shake well. Pour in the slow cooker. Sprinkle Tajin over top if using.

Turn the slow cooker on low for 6 to 8 hours. Use two forks to shred the chicken right in the slow cooker.

Boil the pound of spaghetti in salted water according to package directions (remember to remove half cup of the water right before draining). Drain well and add the pasta, the half cup pasta water, and most of the shredded cheese to the slow cooker. Stir until combined.

Taste for seasoning and add more kosher salt, pepper, chili powder, and/or Tajin if needed. Top with remaining shredded cheese, fresh cilantro, and hot sauce (if using) before serving.