HEAT oven to 350ºF.
COOK onions in large skillet sprayed with cooking spray on medium-high heat 5 to 7 min. or until crisp-tender, stirring frequently. Add cream cheese, broth and sugar; cook 5 to 7 min. or until cream cheese is melted and sauce is well blended, stirring frequently.
PLACE potatoes in 13x9-inch baking dish sprayed with cooking spray; cover with sauce.
BAKE 45 min. Combine cracker crumbs and nuts; sprinkle over potatoes. Bake 10 min. or until potatoes are tender.