Pat chicken dry. Season both sides thoroughly with cumin, chili powder, smoked paprika, garlic powder, onion powder, salt, and black pepper.
Place seasoned chicken in the bottom of the slow cooker in a single layer.
Pour salsa evenly over the chicken. Add black beans and corn around the sides. Squeeze lime juice over everything.
Add optional broth only if the mixture looks very dry.
Cover and cook on LOW for 6 to 8 hours, or HIGH for 3 to 4 hours.
Check internal temperature — it must reach 165°F (74°C).
Shred chicken using two forks directly in the slow cooker. Stir to combine with all the juices.
Let rest 5 minutes before serving.
Serve in tacos, rice bowls, burritos, or quesadillas.