HEAT oven to 400ºF.
PRICK potato in several places with fork. Microwave on HIGH 7 to 8 min. or until tender.
CUT potato lengthwise in half. Scoop flesh into bowl, leaving thin shells; mash potato flesh with cream cheese spread, sour cream and 2 Tbsp. cheddar. Spoon into shells; sprinkle with remaining cheddar.
BAKE 10 min. or until cheese is melted and potatoes are heated through.