01 - Place the chicken breasts or thighs in the bottom of the slow cooker, arranging in an even layer.
02 - Sprinkle the taco seasoning, smoked paprika, salt, and black pepper evenly over the chicken pieces.
03 - Pour the salsa and chicken broth (or water) over the seasoned chicken. Squeeze the juice from one lime directly into the slow cooker.
04 - Cover and cook on high for 4 hours or on low for 7 hours, until the chicken is tender and easily shreds with a fork.
05 - Remove the cooked chicken from the slow cooker and shred thoroughly using two forks. Return the shredded meat to the slow cooker and stir well to coat in the cooking juices.
06 - Warm the taco shells according to package instructions, either in the oven or microwave.
07 - Fill each warm taco shell with the shredded chicken mixture. Top with lettuce, cheese, sour cream, tomatoes, red onion, avocado slices, and fresh cilantro. Serve with lime wedges on the side.