(1) Place caramels and evaporated milk in a heavy saucepan. Heat over medium-low heat, stirring continually, until smooth, about 5 minutes. Stir in 1/2 cup chopped pecans. Pour into piecrust.
(2) Combine cream cheese, sour cream, and milk in a blender. Process until smooth. Add pudding mix; process for about 30 seconds longer.
(3) Pour pudding mixture over caramel layer covering evenly. Chill, loosely covered, until set, about 15 minutes.
(4) Drizzle fudge topping over pudding layer in a decorative pattern. Sprinkle top of cake with remaining pecans. Chill, loosely covered, until serving time. Serves 12.