Add chicken, chicken broth, onion and garlic to slow cooker and cook on the low setting for 3-4 hours.
Meanwhile, cook the tomatillos and peppers in water for 10 minutes or until soft.
Puree the tomatillos, peppers, lime juice and cilantro in a blender. Add this mixture to the crock pot.
Add the prepared beans to the crock pot and cook on low until it reaches the desired consistency.