Preheat oven to 180ºC F. Grease lightly 13x9 inch pan. Stir sugar, flour, cocoa, soda, and salt; set aside. Mix melted butter, eggs and vanilla until smooth. Add flour mixture and stir until moistened. Fold in chocolate chips and nuts. Spread batter in prepared pan. Bake for 35-40 minutes. Do not overbake.