Preheat oven to 180 degrees C. Butter one 23cm springform pan.
Toast the pecans for 6 minutes. Remove pecans and set aside. Leave oven at 180 degrees C. In a small saucepan, melt the unsalted butter.
Combine vanilla wafer crumbs with the melted butter then press into the bottom of the prepared springform pan. Place the pan onto a baking tray and bake for 10 minutes. Remove and allow to cool.
In a double boiler, or a bowl set over barely simmering water, melt the caramels in the evaporated milk. Stir until smooth. Pour this over the cooled crust. Sprinkle the nuts over the top.
In a bowl, combine the cheese, sugar and vanilla and beat until smooth, scraping down the bowl several times. Add the eggs one at a time and beat until smooth. Melt the chocolate chips in the double boiler and mix into the cheese mixture. Pour the batter over the caramel layer.
Bake for 40 minutes or until barely set. Chill overnight in the refrigerator before serving.