1) Place chicken breasts in a crockpot.

2) Combine crushed tomatoes, chilies, chili powder, cumin, salt, sugar, onion and garlic.

3) Pour over chicken. Cover crockpot and cook on low for 8 hours. Shred the chicken with two forks. It should fall apart very easily. Stir in vinegar and cut-up chocolate until chocolate has melted completely.

4) Serve on top of diced cooked yams or cooked rice. Also great in quesadillas or wraps, or in a toasted bun as a sandwich.