Heat oven to 300 degrees Fahrenheit. Mix wafer crumbs, 1/2 cup nuts and butter; press onto bottom of 13 by 9 inch baking dish.
Microwave caramels and milk on medium (50%) 4 to 5 minutes or until caramels are melted and mixture is well blended, stirring every 2 minutes. Pour over crust; spread to within 1 inch of edge. Cool.
Beat cream cheese and sugar in large bowl with mixer until blended. Add sour cream; mix well. Add eggs, 1 at a time, mixing on low speed after each until just blended. Melt 7 chocolate squares. Stir into cream cheese batter; pour over caramel layer.
Bake 45 to 50 minutes or until center is almost set. Refrigerate 4 hours. Sprinkle with remaining nuts just before serving. Melt remaining chocolate square;drizzle over cheesecake.