HEAT oven to 425ºF. Cut potatoes lengthwise in half; place, cut-sides down, in foil-lined 15x10-inch baking pan. Bake 30 to 35 min. or until tender.
SCOOP out centers of potatoes into bowl, leaving 1/4-inch-thick shells. Add Neufchatel cheese, milk, sugar and cinnamon to potatoes; mash until blended. Spoon potato mixture into shells; top with nuts.
BAKE 8 min. or until potatoes are heated through and nuts are toasted.