Place the chicken thighs in the slow cooker. Add the diced onion, minced garlic, diced tomatoes with green chilies, black beans, frozen corn, and chicken broth.
Sprinkle in the chili powder, cumin, and salt. Stir once to distribute the spices.
Add the torn corn tortillas and press them down into the liquid so they are mostly submerged.
Cover and cook on low for 6 hours.
Remove the chicken thighs to a plate, shred with two forks, and return the meat to the slow cooker. Stir well to combine everything.