Heat oven to 375~. In small bowl combine flour, cocoa and baking soda. Mix well. In large bowl beat 1 cup sugar with brown sugar and margarine until light and fluffy. Add vanilla and eggs and beat well. Add flour mixture and blend. Stir in 1/2 cup of nuts. For each cookie, shape about 1 Tb of dough around 1 Rolo, covering completely. In a small bowl combine remaining nuts (ground up pretty fine) with 1 Tb of sugar. Press 1 side of each ball into the nut mixture and place, nut side up, two inches apart on ungreased cookie sheets. Bake at 375~ for 7-10 minutes or until set and slightly cracked. Cool 2 minutes; remove from cookie sheets. Cool completely.