Feel free to adjust the spices as you prefer. Make it more or less spicy. Add oregano or change the cumin amount, etc.. You can also just replace the spices for 1 bag of taco seasoning if you prefer. Chicken thigh or leg meat will be juicer than breast meat, but if you prefer, the breast meat still comes out quite nice. We'll usually prefer boneless, skinless but feel free to use whatever you have available.
For the Chicken
2poundschicken, preferrably boneless and skinless (*see head note)
Add all the ingredients into the slow cooker (chicken, tomato sauce or salsa, Worcestershire sauce, chili powder, cumin, onion powder, garlic powder, salt & pepper, and optional chipotle powder). Stir to completely coat the chicken with the spices & sauce.
Slow cook 6-8 hours on low or 4-5 hours on high.
Take the chicken pieces out of the slow cooker, cut into 1-2 inch pieces, then place back in the slow cooker. Shed with a couple forks to break up the chicken.
Taste the chicken and add more salt if needed.
When ready to serve, top the lettuce with the shredded chicken and with whatever other preferred toppings you like.