Prepare the slow cooker by greasing it lightly.
Place the chicken thighs in the slow cooker.
Add the diced onion and minced garlic on top of the chicken.
Pour in the can of green chilies along with the chicken broth.
Sprinkle the cumin and chili powder over the top, and season with salt and pepper.
Cover the slow cooker and cook on low for 6 to 7 hours or on high for 3 to 4 hours.
Check the doneness of the chicken; it should shred easily.
Once done, shred the chicken directly in the slow cooker.
Serve hot, over rice or in tortillas, garnish if desired.