HEAT oven to 325°F.

MIX crumbs and butter; press onto bottom and 2 inches up side of 9-inch springform pan.

MICROWAVE caramels and milk in small microwaveable bowl on HIGH 3 min. or until caramels are completely melted, stirring after each minute. Stir in nuts; pour half into crust. Refrigerate 10 min. Refrigerate remaining caramel mixture for later use.

BEAT cream cheese, sugar and vanilla with mixer until well blended. Add eggs, 1 at a time, mixing on low speed after each just until blended. Pour over caramel layer in crust.

BAKE 1 hour 5 min. to 1 hour 10 min. or until center is almost set. Run knife around rim of pan to loosen cake; cool before removing rim. Refrigerate 4 hours.

MICROWAVE reserved caramel mixture 1 min.; stir. Pour over cheesecake. Melt chocolate as directed on package; drizzle over cheesecake.