Don Nelson, second-winningest NBA coach who won 5 titles as a Celtics player, dies at 86Photo by: Jeff Chiu/AP FILE - Former Golden State Warriors head coach Don Nelson smiles while being interviewed at the Warriors NBA training facility in Oakland, Calif., Tuesday, Aug. 28, 2012. (AP via SCRIPPS NEWS GROUP) – Don Nelson, the second-winningest coach in NBA history who won five championships as a player with the Boston Celtics, died Sunday. Nelson’s death was announced by the Golden State Warriors, one of the teams he coached. His fast-paced offenses were probably best on display with Golden State in the “Run TMC” era featuring future Hall of Famers Tim Hardaway, Mitch Richmond and Chris Mullin. In his final season as a coach, Nelson mentored rookie Stephen Curry in 2009-10.