In a nonstick skillet coated with cooking spray, brown chicken over medium heat. Transfer to a 13-in. x 2-in. baking dish coated with cooking spray.
Remove skillet from stovetop and recoat with cooking spray; cook onion over medium heat until tender. Stir in remaining ingredients. Bring to a boil. Reduce heat; simmer, uncovered, for 15 minutes. Pour over chicken. Bake, uncovered, at 350 degrees for 45-55 minutes or until chicken juices run clear and a meat thermometer reads 170 degrees.