Spray 4- to 5-quart slow cooker with cooking spray. In slow cooker, mix beef, seasoning mix, onions, garlic, jalapeño chile, 1/2 cup of the barbecue sauce, the water and vinegar. Cover; cook on High heat setting 4 to 5 hours, or Low heat setting 8 to 9 hours or until tender. Transfer beef to cutting board; shred with two forks. Return to slow cooker with remaining 1/4 cup barbecue sauce. Stir to combine.