Preheat oven to 375 degrees. Soften butter or margarine. In a mixing bowl cream the softened butter, shortening, brown sugar, and granulated sugar. (Cream well) Add eggs and vanilla: beat well. In a bowl stir together the flour, baking soda, and salt. Add to the creamed mixture and stir until well blended. Stir in chocolate pieces and nuts. Drop from a tablespoon or scoop using the Pamper Chef medium scoop onto an ungreased cookie sheet . Bake in oven for 8- 10 minutes. For a soft cookie remove while the cookie is still quite soft. It will " harden up" as it cools. Bake longer for a chewier cookie. Cool on a wire rack. Enjoy!