In the world of dreams the rules of reality do not necessarily apply. Each dream is unique and it's a direct link to the soul and spirit. Psychology provides its own theories on what dreams mean, but so did tradition and the study of dreams for thousands of years before any relevant science had developed.
Dream Meanings - Chestnuts
If you dream that you are eating cooked chestnuts then you will have a distressing argument with a friend, but if you eat roasted chestnuts be careful to avoid getting involved in an unpleasant situation.