Mix 2 cups of chocolate crumbs with melted butter, nuts and sugar. Press onto bottom of pan and up the sides. Bake for 10 minutes. Remove and set aside.
Beat cream cheese, sugar and vanilla with mixer until blended. Add sour cream, mix well. Add eggs, one at a time, beating on low after each one until just blended. Pour entire bag of chips into mixture and stir until blended. Pour over crust.
Bake 40 minutes to 60 minutes or until center is almost set. Cool completely and refrigerate over night.
Spread chocolate fudge topping over top of cheesecake and sprinkle Ghirardelli chocolate shavings all over top.