01 - Arrange the chicken breasts or thighs in an even layer at the bottom of the slow cooker insert.
02 - Dust the chicken evenly with taco seasoning, smoked paprika, salt, and black pepper, ensuring all pieces are coated.
03 - Pour the salsa and chicken broth (or water) over the seasoned chicken. Squeeze fresh lime juice across the top.
04 - Cover with the lid and cook on high setting for 4 hours or low setting for 7 hours, until the chicken is fully cooked and tender enough to shred easily.
05 - Transfer the cooked chicken to a cutting board or large plate. Use two forks to pull the meat apart into shredded pieces.
06 - Return the shredded chicken to the slow cooker and stir thoroughly to absorb all the cooking juices.
07 - Heat the taco shells according to package directions, either in the oven, microwave, or on a dry skillet.
08 - Fill each warmed shell with a generous portion of shredded chicken, then layer with lettuce, cheese, sour cream, tomatoes, red onion, avocado, cilantro, and a squeeze of fresh lime. Serve immediately.