In a bowl, whisk the first 6 ingredients until combined. Pour half into a shallow glass dish. Cover and refrigerate remaining lemonade mixture. , Dip chicken into lemonade mixture, turning to coat; discard lemonade mixture. Grill chicken, covered, over medium heat for 30 minutes, turning occasionally. Brush with reserved lemonade mixture. Grill 10-20 minutes longer, brushing frequently, until a thermometer reads 165°.