Heat oven to 375 F. Beat together margarine and sugars until light and fluffy. Beat in egg and vanilla. Combine flour, baking soda and salt; add to margarine mixture, mixing well. Stir in oats, chocolate pieces and nuts. Drop by rounded teaspoonfuls onto ungreased cookie sheet. Bake 9 to 11 minutes. Cool 1 minute on cookie sheet; remove to wire rack. Store in tightly covered container. NUTRITIONAL ANALYSIS per cookie: * calories 102 * carbohydrates 11 g * protein 1 g * fat 6 g * calcium 8 mg * sodium 55 mg * cholesterol 4 mg * dietary fiber 0 g