Heat oil in large pot over medium high heat. Add onions and saute until translucent, about 10 minutes. Stir in garlic, then chilies, cumin, oregano, and cayenne and saute 2 minutes. Add undrained beans and stock and bring to a boil. Reduce heat and add chicken and cheese to chili and stir until cheese melts. Season to taste with salt and pepper and ladle into bowls. FOR FREEZING: Pour soup into a rigid container (or freezer bag), label and freeze. To reheat, thaw in refrigerator overnight or simply put frozen soup into a largepot and gently heat, with lid on and stirring often, till heated through.