In a large skillet over medium-high heat, melt butter with olive oil. Sprinkle chicken with salt; add to skillet. Cook, turning occasionally until browned on all sides (about 10 min.). Move chicken to a baking sheet sprayed with cooking spray; bake in a preheated 425° oven until chicken reaches an internal temperature of 165°, turning once (20-25 min.). Working in batches, transfer chicken to a large mixing bowl; toss with sauce to coat. Serve immediately.