Good discovery. Let us know if you need any particular help with your research into their service.
By the way, have you been to any of the Peninsula Campaign/Seven Days battlesites at which your relative Reuben Chandler fought? Williamsburg, Seven Pines, Mechanicsville (Beaver Creek Dam), Gaines Mill, and Malvern Hill are all within 2 hours of your home. There's not much left of the earthworks at Williamsburg, but enough to make a visit worthwhile, and Seven Pines has been lost to development, but the others have substantial pieces of battlefield preserved by the National Park Service (Richmond Battlefield Unit) and make for some great battlefield touring. It's extra special to walk the lines your ancestor defended/attacked.