HEAT oven to 375ºF.
MIX first 5 ingredients, 3/4 cup shredded cheese and 2 Tbsp. Parmesan just until blended; shape into 18 meatballs, using about 2 Tbsp. for each. Place on rimmed baking sheet sprayed with cooking spray.
BAKE 15 min. or until done (160ºF). Meanwhile, cook spaghetti as directed on package omitting salt, and heat spaghetti sauce in separate large saucepan.
DRAIN spaghetti; place on platter. Stir meatballs into sauce; spoon over spaghetti. Sprinkle with remaining cheeses.