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.
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.
See note below about taco shell options. Build your tacos and serve or have everything in bowls for everyone to make their own tacos.
For soft tortillas, we love to char them a little over a burner, or at least to warm them in the microwave. After warming, cover them in a kitchen towel, paper towels, or foil to help keep them softened and not dry out.
For hard shells, warming them in the oven or air fryer a bit before serving makes them extra tasty.