Lightly butter a 23 cm springform pan. Crush the cookies. Stir in the melted butter and mix well. Press into the prepared pan. Chill until firm. In a heavy saucepan, melt the chocolate with the butter over low heat. Stir in the sugar. Slowly pour in the evaporated milk. Cook over high heat for 5 to 10 minutes, or until thickened. Transfer to a bowl. Chill in the freezer until the ice cream is firm. Spread with the chocolate sauce. Return to the freezer. Whip the cream with the sugar and Kahlua until firm. Spread over the pie. Sprinkle with the chopped nuts. Freeze until firm, about 4 hours. Let stand for 5 minutes before serving.