Spray 4-quart slow cooker with cooking spray. In 12-inch nonstick skillet, heat oil over medium-high heat. Cook chicken in oil 8 to 10 minutes, turning occasionally, until brown on both sides (cook a few pieces at a time if all don’t fit in skillet).
Place chicken in slow cooker. Cover; cook on Low heat setting 6 to 7 hours or until chicken is tender. About 30 minutes before serving, in 1-quart saucepan, heat sauce ingredients over medium heat 10 to 15 minutes, stirring occasionally, until thickened.
Drain excess liquid from slow cooker. Pour sauce over chicken; cook 10 to 15 minutes longer.