Preheat oven to 350°F. Grease a 13x9 pan. Place graham crackers in a blender and process until crackers form fine crumbs. Measure 2 cups of crumbs and combine with chocolate chips, coconut and walnuts in medium bowl; stir to blend. Add milk; stir with mixing spoon until blended. Spread batter evenly into prepared pan and bake 15 - 18 minutes or until edges are golden brown. Let pan stand on wire rack until completely cooled. Cut into bars. Store tightly covered at room temperature or freeze up to 3 months.