01 - Place the chicken breasts in the bottom of the slow cooker in an even layer.
02 - Sprinkle the ranch seasoning mix, garlic powder, onion powder, smoked paprika, and black pepper evenly over the chicken breasts.
03 - Pour the chicken broth and the can of diced tomatoes with green chilies (including juices) over the seasoned chicken.
04 - Cover the slow cooker and cook on low for 4 to 5 hours, or on high for 2 to 3 hours, until the chicken is tender and reaches an internal temperature of 165°F.
05 - Remove the chicken from the slow cooker and shred using two forks. Return the shredded chicken to the slow cooker, stir to combine with the cooking juices, and let rest for 10 minutes to absorb the flavors.
06 - Warm the taco shells or tortillas according to package instructions.
07 - Divide the shredded ranch chicken evenly among the warmed taco shells. Top with shredded lettuce, cheddar cheese, sour cream, diced tomatoes, and fresh cilantro as desired. Serve immediately.