Preheat the oven to 350°. In a nonstick skillet coated lightly with oil, brown the chicken over medium heat. Transfer to a 13x9-inch baking dish coated with cooking spray.
Recoat the skillet with oil. Add the onion; cook and stir over medium heat until tender.
Stir in the remaining ingredients and bring them to a boil. Reduce the heat and simmer, uncovered, for 15 minutes. Pour over the chicken.
Bake, uncovered, until a thermometer inserted in the chicken reads 170°. This takes 35 to 45 minutes. Editor's Tip: Let the baked chicken sit in its juices for a few minutes before serving. This will ramp up the flavor.
