Preheat the oven to 350 degrees.
In a large bowl, cream together the butter, granulated sugar and brown sugar, vanilla, and the egg. Mix the flour, baking powder, baking soda, and salt together in another bowl. Add to the creamed butter and sugar mixture. Stir just until the dough is stiff. Stir in the nuts and chocolate. Form the cookies using 2 soup spoons and place them 2 inches apart on ungreased cookie sheets. Bake until light brown, 20 to 25 minutes. Remove from the oven. Cool slightly, then remove with a spatula and cool completely on wire racks.
Makes about 26 large cookies