Beat butter and shortening at medium speed with an electric mixer until creamy; add chunky peanut butter and sugars, beating well. Add eggs, beating until blended.
Combine flour and next 5 ingredients. Add to butter mixture, beating well.
Stir in peanuts and chocolate chunks.
Shape dough into 2-inch balls (about 2 tablespoons for each cookie). Flatten slightly, and place on ungreased baking sheets.
Bake at 375° for 12 to 15 minutes or until lightly browned. Cool on pan 1 to 2 minutes; remove to wire rack to cool completely.