Heat oven to 350'F. Lightly grease 2 large cookie sheets. Beat sugar and margarine until fluffy. Blend in eggs and vanilla. Add combined flour, baking soda, salt and oats; mix well. Stir in chocolate pieces and nuts. Divide dough in half. Press each half into circle about 3/4" thick on prepared cookie sheets. Bake 17-20 minutes or until lightly browned. Cool 5 minutes on cookie sheets; remove to wire racks. Cool completely. Cut into wedges to serve. Makes 2 giant cookies. VARIATION: Drop dough by rounded tablespoonfuls onto ungreased cookie sheets. Bake 10-12 minutes. Makes about 3 dozen cookies.