Heat oil in a large skillet. Season chicken with salt and black pepper.Add chicken,do not crowd pieces,brown chicken turning over several times to brown evenly.May need to do this in batches,pour off oil.Add additional oil, onions,brown lightly,remove from pan,add mushrooms and garlic, brown them slightly. Remove veggies and oil. Add chicken,garlic and onions and enough broth about halfway of the chicken,cook on medium high,adding additional broth when broth cooks out. Cook until chicken is very tender,falling apart,add mushrooms back into the skillet about 10 minutes before chicken is tender.