Place the chicken breasts in the bottom of the crockpot.
Add beans, onion, garlic, green chilies, corn, and all seasonings on top of the chicken.
Pour in the chicken broth until ingredients are just covered.
Cover and cook on low for 6–8 hours or high for 3–4 hours, until chicken is tender.
Remove the chicken, shred with two forks, and return it to the crockpot.
If using, stir in masa mixture and cook for 15–20 minutes to thicken.
Finish with lime juice or cheese if desired, then taste and adjust seasoning before serving.