HEAT oven to 400ºF.
CUT potatoes in half lengthwise; scoop out centers into medium bowl, leaving 1/8-inch-thick shells.
BEAT potatoes and cream cheese with mixer until blended. Add milk and chili powder; beat until fluffy. Stir in onions; spoon into shells. Place on baking sheet. Sprinkle with bacon.
BAKE 20 to 25 min. or until heated through.