Place the chicken thighs in the slow cooker. Sprinkle chili powder, cumin, smoked paprika, garlic powder, and salt over the meat.
Pour the salsa on top. Cover and cook on low for 6 hours or high for 3 hours until the chicken is very tender.
While the chicken cooks, combine the diced tomatoes, red onion, cilantro, jalapeno, and lime juice in a bowl. Stir to mix the pico de gallo and set it aside.
Once the chicken is done, shred it directly in the slow cooker using two forks and stir it into the juices.
Warm the corn tortillas in a dry skillet or microwave. Spoon the shredded chicken into each tortilla and top with a generous scoop of pico de gallo.