In the bowl of your slow cooker, combine the chicken, onion, garlic, oregano, salt, chipotle peppers, and orange juice. Cover and cook on LOW for 6-7 hours or on HIGH for 4-6 hours. Once the chicken is done cooking, shred with two forks and stir in the lime juice and cilantro.
To make the slaw, in a bowl, combine the cabbage, pineapple, jalapeño, cilantro, olive oil, vinegar, lime juice, and a pinch of salt.
Stuff the chicken into the warmed taco shells and top with slaw, cheese, and mashed avocado. Enjoy!
