Combine 13 crushed cookies and frosting; spread in a 9-inch square dish. Freeze 15 minutes.
Combine milk, pudding, and next 3 ingredients in a large bowl; beat at medium speed with an electric mixer 2 minutes.
Spread half of pudding mixture over cookie layer in dish; sprinkle with 14 chopped cookies. Drizzle 1/3 cup chocolate syrup over chopped cookie layer. Carefully spread remaining half of pudding mixture in dish. Cover and chill 30 minutes.
Beat cream cheese and powdered sugar at medium speed with an electric mixer until creamy; fold in whipped topping. Spread cream cheese mixture over pudding layer. Sprinkle with walnuts, and drizzle with 1/4 cup chocolate syrup. Cover and chill 8 hours. Store in refrigerator.
*To make your own cinnamon sugar, combine 1/2 cup sugar and 1 tablespoon ground cinnamon.