Keep aside the coconut milk for an hour or so, so that the cream of coconut seperates on top. Cook Potato and cube. Cut chicken to 1-2 inch pieces. Heat oil in a deep pan and fry chopped onion till brown. Add chicken,all the spices and cream of coconut, mix well and cook covered on medium heat till chicken is almost cooked, about 15-20 minutes. Add the reamining coconut milk and cook on medium heat for about 10 minutes.