Toss the chicken in the flour, then shake off any excess.
Heat the oil in a wide frying pan, and sauté the chicken quickly until sealed and lightly browned, then remove from the pan.
Add the onion to the pan and gently sauté until soft. Add the garlic, peppers, tomatoes and the 1 tablespoon chopped oregano, then bring to the boil, stirring.
Arrange the chicken over the vegetables, season well with salt and pepper, then cover the pan tightly and simmer for 20–25 minutes until the chicken is tender and the juices run clear. Check the seasoning, adjusting if necessary.
Garnish the chicken with the extra oregano, and serve hot.