Combine sugar, margarine, and milk in heavy 2 1/2 quart saucepan; bring to full rolling bowl, stirring constantly. Continue boiling 5 minutes over medium heat or until candy thermometer reaches 234' stirring constantly to prevent scorching. Remove from heat; stir in chips until melted. Add marshmallow creme, nuts and vanilla; beat until well blended. Pour into greased 9x13 inch pan. Cool at room temperature, cut into squares. Makes approx 3 pound.