Combine first 6 ingredients in a medium bowl; stir well. Stir in chocolate chips and nuts. Pour into pastry shell; bake at 425° for 10 minutes. Reduce oven temperature to 350° and bake 30 more minutes or unil set. (Cover edges of pastry with strips of aluminum foil to prevent excessive browning, if necessary.)
Cool completely on a wire rack; cover and chill thoroughly.
Coffee Cream: Combine all ingredients in a large bowl; beat at high speed with an electric mixer until stiff peaks form.
To serve, dollop each serving with Coffee Cream and sprinkle with shaved chocolate.