Heat oil in a medium saucepan over medium high heat, add onion and garlic. Saute for 1-2 minutes until soft. Add cumin and oregano, allow to toast for another minute. Add flour to make a roux. Wisk in chicken stock, reduce heat to low. Add green chiles and season with salt. Simmer for 5-10 minutes until beginning to thicken. Just before ready to serve, stir in sour cream and mozzarella allowing cheese to melt completely. Adjust seasoning if needed. ??