1. Heat oven to 375°F. Remove wrappers from chocolate pieces.
2. Beat beat butter, shortening, granulated sugar and brown sugar in large bowl until fluffy. Add eggs; beat well. Stir together flour, baking soda and salt; add to butter mixture, beating until well blended. Stir in rolled oats and nuts. Shape rounded teaspoons of dough into 1-inch balls. Place on ungreased cookie sheet.
3. Bake 8 to 10 minutes or until light brown. Remove from oven; immediately place chocolate piece in center of each cookie, pressing down lightly. Carefully remove cookies from cookie sheet to wire rack. Cool completely. Makes about 6 dozen cookies.