In a medium pot heat oil over medium high heat. Add onions and fry until translucent then add the coriander stalks, green chiles and garlic and fry for a further 3 minutes.
Add stock, salsa verde, cumin and dried oregano. Mix together and cook for 15. Add the beans and cook for 15 more minutes.
Serve with freshly squeezed lime juice, chopped coriander and other toppings like grated cheese and sour cream if you wish.
To make the parmesan tortilla chips, preheat the oven to 180 C. Cut the flour tortillas into triangles and sprinkle with grated cheese. Place in the preheated oven for 3 - 5 minutes until golden and the cheese has melted. Serve with the soup.