HEAT oven to 350°F.
COMBINE olive oil and oats. Let stand 5 minutes. Stir in cake mix, eggs and vanilla until well blended. Fold in nuts. Form into 1-inch balls and place about 2 inches apart on ungreased cookie sheet.
BAKE 8 minutes or until set. Cool on cookie sheet 1 minute. Remove cookies to cooling rack. Roll in powdered sugar while still slightly warm.