Saute onions with garlic salt in a large, heavy bottomed pan in the olive oil over medium-high heat for 10 minutes or until very soft. Add garlic and saute 2 minutes more, then add chicken and saute until chicken is no longer pink. Add broth, chiles, beans, hominy, cumin, oregano, chile powder if using and cayenne and stir to combine. Bring to a boil, then lower to simmer for 30 minutes. Turn heat down to low and add sour cream, blending well. Cook for 5 minutes more, then serve hot. Top with additional sour cream, shredded Monterey Jack cheese and crushed tortilla chips.