COMBINE shortening, granulated sugar, brown sugar, eggs, buttermilk and vanilla in large bowl; beat at medium speed of electric mixer until light and fluffy.
COMBINE flour, oats, baking soda and salt in small bowl. Add gradually to shortening mixture at low speed until well blended. Stir in chocolate chips and nuts. Cover. Refrigerate at least 30 minutes.
HEAT oven to 325 degrees F. Coat baking sheet with no-stick cooking spray.
DROP dough by rounded or heaping teaspoons 3 inches apart onto prepared baking sheet.
BAKE 14 to 16 minutes or until light golden brown. Cool 2 minutes on baking sheet before removing to cooling rack to cool completely.