Cook the diced chicken in the oven until just cooked but not over coloured.
Dice the onions and peppers and crush the garlic for the sauce, put in a saucepan with a little olive oil and sweat until soft. Add the rest of the sauce ingredients and base sauce. Cook for 15 minutes on a low heat. Taste and adjust seasoning if necessary.
Add the cooked chicken to the tomato sauce and stir thoroughly.
Place into serving dishes and garnish with chopped parsley.