Add the chicken broth, lime juice, adobo sauce, cumin and salt into a small bowl.
Chop the cilantro and chipotle peppers, add them to the bowl and mix well.
Place the chicken breasts in a single layer in the slow cooker.
Pour the sauce over the chicken.
Set the cooker to high and cook for 2.5-3 hours, depending on your cooker. You will know the chicken is done when it flakes easily when you insert a fork and twist. If you would rather cook these on low, they will take 4-5 hours.
Remove the chicken from the pot and place it in a bowl. Shred the chicken with 2 forks, then pour some of the sauce from the slow cooker over the shredded chicken. You can use as much or as little as you like.
Fill your taco with chicken and any optional topping you choose and serve.
Nutrition information provided is an estimate and does not include optional toppings.