To the crockpot, add chicken, onion, teriyaki sauce, cumin, smoked paprika, garlic powder , lime juice and 2 cups of the pineapple (reserve one cup for serving). Give everything a big stir and cook on HIGH for 3 1/2 to 4 hours or on LOW for 6-7 hours.
While chicken is cooking, make the slaw dressing. Whisk together sour cream, milk, chipotle, adobo sauce, salt, cumin and lime juice. Taste and add more salt to your liking. Cover and refrigerate until ready to serve.
When chicken is done cooking, carefully remove it from crockpot. With two forks, shred chicken then return it to crockpot. Give it a stir and coat chicken in all the delicious juices!
When you are ready to serve, heat tortillas. I like to wrap 2-3 in a clean dish towel and heat them in the microwave for 15-30 seconds.
Toss together coleslaw mix, cilantro (if using) and about 1/2 of the dressing. Reserve the other half of the dressing for drizzling on top of the tacos!
To assemble tacos: top tortillas with chicken mixture, reserved pineapple, slaw and more of the slaw dressing, if desired! Add a squeeze of lime and enjoy!