Heat oven to 375°F. In large bowl, beat margarine and sugars until creamy. Add eggs, milk and vanilla; beat well. Add combined flour, baking soda and salt; mix well. Add oats, chocolate chips and nuts, if desired; mix well. Drop dough by rounded tablespoonfuls onto ungreased cookie sheets. Bake 9 to 10 minutes for a chewy cookie or 12 to 13 minutes for a crisp cookie. Cool 1 minute on cookie sheets; remove to wire rack. Cool completely. Store tightly covered.