PREHEAT oven to 325°F. Mix flour and baking soda; set aside. Beat margarine and sugars in large bowl with electric mixer on medium speed until light and fluffy. Blend in coffee, egg and vanilla. Add flour mixture; beat until well blended. Stir in chocolate chunks and walnuts; cover. Refrigerate 30 min.
ROLL dough into 1-inch balls; place, 2 inches apart, on ungreased baking sheets.
BAKE 10 to 12 min. or until golden brown. Remove from baking sheets to wire racks. Cool completely. Store in tightly covered container at room temperature.