Beat butter with sugar until mixture is light and fluffy. Beat in vanilla.
Blend salt with flour and stir into beaten mixture, mixing well. Fold in chocolate pieces and nuts. Press into ungreased 15½ X 10½ X 1" jelly roll pan.
Bake in moderate oven (350°) 20 minutes. While warm, cut in 2½ X 1½" bars. Cool in pan on rack.