HEAT oven to 400ºF.
UNROLL pie crust; sprinkle with half the flour. Turn; sprinkle with remaining flour. Press firmly onto bottom and up side of 9-inch pie plate; flute edge.
WHISK next 5 ingredients until blended. Stir in nuts; pour into crust. Sprinkle with chocolate.
BAKE 15 min. Reduce oven temperature to 350ºF. Continue baking 30 to 35 min. or until top is puffed and lightly browned. Cool completely, sprinkling with salt after 15 min.