Combine the chocolate wafer cookie crumbs, pecans and butter or margarine and mix well. Press into the bottom and 1/2 up the sides of one 9 inch springform pan.
In a large bowl, with and electric mixer on medium speed, beat together the cream cheese and brown sugar substitute until fluffy. Beat in the eggs, vanilla and espresso until smooth and well blended. Approximately 2 minutes. Add the flour and sour cream and beat until smooth. Scrape filling into the prepared crust and smooth top.
Bake at 400 degrees F (205 degrees C) for 15 minutes then reduce oven temperature to 300 degrees F (150 degrees C) and continue baking for 25 to 30 minutes or until cheesecake is set around the edges but still jiggles slightly in the center. Let cake cool for 2 to 3 hours then refrigerate until well chilled. Approximately 6 hours or overnight. One hour before serving, run a knife around the edge of the pan and remove the cake from the springform pan. Slice and serve.