Place the 2 lb boneless skinless chicken breasts in the base of a 6‑quart slow cooker in a single layer if possible.
Sprinkle the chicken evenly with the 1 oz package of taco seasoning and the 1 oz package of ranch dressing mix.
Pour 1/2 cup low-sodium chicken broth around the chicken to add moisture.
Cover and cook on LOW for 4 to 6 hours, until the chicken is cooked through and easily shreds with two forks.
Remove the chicken, shred with two forks, then return to the slow cooker and stir to combine with the cooking juices before serving in tacos.