Combine onion powder, cumin, oregano, chili powder, and paprika together in a bowl to create taco seasoning.
Place chicken breasts in the bottom of a slow cooker. Add green bell pepper, red bell pepper, salt, pepper, and taco seasoning. Pour in broth, ensuring chicken is just covered in liquid.
Set slow cooker to Low; cook for 6 hours.
Break up chicken breasts with a wooden spoon. Add beans; cook on Low for 30 minutes more.