Rub the pork loins with olive oil, salt and pepper. Heat one tablespoon olive oil in a large, deep, non-stick skillet and brown the pork. Add the onions and stir for 2-3 minutes, just until softened. Raise the heat and pour in the wine. As soon as it steams up, add the tomatoes, bay leaves, and half the chestnuts. Cover and simmer for 10 minutes. Preheat the oven to 180˚C/350˚F.