Cream butter, sugar and vanilla in small bowl at medium speed with electric mixture until light and fluffy. Finely chop graham crackers and add to mixture. Press into bottom of springform pan.
Bake in the preheated oven for 15 minutes.
Beat cream cheese, sugar and vanilla at medium speed with electric mixer until well blended. Add eggs one at a time, mixing at low speed after each addition, just until blended. Blend in melted chocolate. Add chopped nuts.
Bake in the preheated oven 55 to 60 minutes.
Garnish with grated milk chocolate and powdered sugar.