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