Preheat oven to 180 C / Gas 4. In a medium bowl, combine digestive biscuit crumbs, ground pecans, sugar, cinnamon, mixed spice and nutmeg. Pour in the melted butter. Mix well and press into the bottom of a 23cm springform cake tin.
In a large bowl, Beat cream cheese, 100g sugar and vanilla until smooth. Beat in the eggs one at a time. Pour filling over base.
Bake in the preheated oven for 70 minutes, or until filling is set. Allow to cool.
In a small bowl, combine toffee sauce and chopped pecans. Spread evenly over cooled cheesecake. Refrigerate at least 4 hours before serving.