Heat the oil in a pan lidded pan, add the chicken, onion and garlic and cook for around 5 mins until golden.
Add the chilli and fry for 30 seconds, then add the tomatoes, stock and oregano (and kidney beans if you are using them) season with salt and pepper and bring to a boil. Cover and simmer for 20mins until the chicken is tender.
When cooked, stir in the cornflour and simmer for a few more mins until the sauce has thickened a little.
Serve with a dollop of soured cream on top, boiled rice and tortilla chips.