1. Stir tomato sauce, chiles, vinegar, honey, paprika, tomato paste, Worcestershire sauce, mustard, ground chipotle and salt in a 6-quart slow cooker until smooth.
2. Add chicken, onion and garlic; stir to combine.
3. Put the lid on and cook on low until the chicken can be pulled apart, about 5 1/2 hours.
4. Transfer the chicken to a cutting board and shred with a fork. Return the chicken to the sauce, stir well and serve.