Place chicken breasts, 3 tbsp Tone's® Taco Seasoning, and chicken broth in slow cooker.
Cover and cook on high for 2-3 hours or low for 4-6 hours, or until chicken is cooked through and shreds easily with a fork. You can use an instant read thermometer to check that the internal temperature of the chicken has reached at least 165° F.
Remove the chicken from the slow cooker, leaving the broth in the pot. Let the chicken cool slightly and then shred the chicken by using either two forks, your hands, or a stand mixer fitted with the paddle attachment. Stir in about ½ cup of the broth from the pot for flavor and moisture.
Add 1 tbsp Tone's® Taco Seasoning, sour cream, and taco sauce to the shredded chicken; stir.
To assemble the tacos, place a piece of romaine lettuce on a tortilla. Top with desired amount of the shredded chicken and toppings of your choice. (We like chopped red onion, diced avocado, cherry tomatoes, and a sprinkle of cheese!)