1.
HEAT oven to 375ºF. Lightly coat a 13 x 9 x 2-inch baking pan with no-stick cooking spray. Cut tops off peppers. Remove and discard seeds and ribs. Place peppers in prepared pan.
2.
HEAT oil in medium skillet over medium-high heat. Add onion and garlic, sautéing 3 minutes or until onions are translucent. Place mixture into medium bowl. Combine onion mixture with chicken, rice, spaghetti sauce, 1/2 cup cheese, salt and pepper. Divide mixture evenly into prepared peppers. Cover with aluminum foil.
3.
BAKE 40 to 50 minutes or until peppers are tender when pierced with tip of paring knife and filling is heated through. Remove from oven (do not discard foil). Top each pepper with 2 tablespoons of remaining cheese; replace foil and let stand just until cheese is melted. Serve.