HEAT oven to 375ºF.
COOK onions and bacon in large nonstick skillet on medium heat 7 to 8 min. or until onions are crisp-tender.
PLACE potatoes in 13x9-inch baking dish sprayed with cooking spray. Add apples, apple juice and cinnamon; mix lightly. Top with onion mixture; cover.
BAKE 40 min.; top with nuts. Bake 15 min. or until potatoes are tender and most the liquid is absorbed.