Healthy Low Fat BBQ Slow Cooker Pulled Chicken

1 8-ounce can reduced-sodium tomato sauce
1 4-ounce can chopped green chiles, drained
3 tablespoons cider vinegar
2 tablespoons honey
1 tablespoon sweet or smoked paprika
1 tablespoon tomato paste
1 tablespoon Worcestershire sauce
2 teaspoons dry mustard
1 teaspoon ground chipotle chile
1/2 teaspoon salt
2 1/2 pounds boneless, skinless chicken thighs, trimmed of fat
1 small onion, finely chopped
1 clove garlic, minced

Stir tomato sauce, chiles, vinegar, honey, paprika, tomato paste, Worcestershire sauce, mustard, ground chipotle and salt in a crock pot until well blended. Add chicken, onion and garlic; stir to mix. Cook in slow cooker on low until the chicken pulls apart easily for about 5 hours. When done cooking, shred with a fork. Return the chicken to the sauce, stir well and serve on buns.