PREPARATION:

1. Preheat oven to 350°F. Line 8-inch square baking pan with foil, pressing foil into corners to cover completely and leaving 1-inch overhang on sides.
2. Spread oats on ungreased baking sheet. Bake 8 to 10 minutes or until light golden brown. Let cool; place in large bowl. Reduce oven temperature to 325°F. Spread hazelnuts and walnuts on baking sheet. Bake 9 to 11 minutes or just until cut sides begin to brown lightly. Let cool; add to toasted oats. Stir in powdered sugar; set aside.
3. Heat chocolate chips and shortening in small heavy saucepan over very low heat, stirring constantly, until melted and smooth. Remove from heat. Spread evenly on bottom of prepared 8-inch square pan. Let stand in cool place 15 to 20 minutes or until chocolate mixture begins to set, but is not firm.
4. Combine butter and salt in microwavable bowl. Microwave on HIGH 20 to 30 seconds or until butter is melted and foamy. Stir in corn syrup; let cool slightly and add vanilla. Stir corn syrup mixture into oat mixture just until moistened. Gently spoon over chocolate, spreading evenly into corners. Score lightly into 4 strips, then score each strip into 6 pieces. Cover tightly with plastic wrap and refrigerate at least 4 hours or until firm.
5. Remove bars from pan, lifting foil by edges. Place on cutting board; cut along score lines into 24 pieces. Remove foil. Store in airtight container in refrigerator.