The basketball world is mourning the loss of legendary coach Don Nelson, who passed away on Sunday. One of them was Jason Kidd, who sent a powerful message following Nelson's death. Don Nelson was a great player, a coaching genius, and a great person. Don Nelson was a great player, a coaching genius and a great person. Like Nelson, Kidd became a coach after his playing career, including calling the shots for the Bucks and the Mavericks as well.