What happened: Nelson's family announced his death Sunday morning. He earned three NBA Coach of the Year awards before entering the Basketball Hall of Fame in 2012.
Why it matters: Nelson's 1,335 coaching victories rank second in NBA history. He received the Chuck Daly Lifetime Achievement Award in 2025.
By the numbers: Nelson won NBA titles with the Boston Celtics in 1966, 1968, 1969, 1974 and 1976. His Coach of the Year awards came in 1983, 1985 and 1992.
What to watch: Memorial arrangements and tributes across the NBA will follow.