NBA's New Coach's Challenge Rule Explained
By Michael Luciano

Fans who were watching the Toronto Raptors kick off the season against the New Orleans Pelicans saw Raptors head coach Nick Nurse become the first to use the NBA's new coach's challenge in a game, when he unsuccessfully lobbied for an offensive foul on guard Norman Powell to be overturned.
Nick Nurse became the first coach in NBA history to issue a coach's challenge last night.
— NBA TV (@NBATV) October 23, 2019
Watch here ?: https://t.co/u8QfIH1IKh pic.twitter.com/FDtsoTLbz0
What is the NBA Coach's Challenge?
Each team will get one challenge, and you must have a timeout remaining to use it. If the challenge is proven correct, the challenging team does not lose a timeout, while they will be docked one timeout if they are wrong.
The league experimented with this system in the G League, but the NBA rules do not allow you to challenge shooting fouls like in the G League. The only calls that can be challenged are personal fouls, a called out-of-bounds violation, goaltending, or basket interference.
The first challenge of the NBA season is confirmed.
— Andrew Lopez (@_Andrew_Lopez) October 23, 2019
Nick Nurse challenged an offensive foul call on Normal Powell but the play stood as called. https://t.co/NZuRmnYvBI
Proponents of this system are thrilled that refs can be held accountable, but those against it note how it can slow down the game.
The idea of allowing coaches the power to challenge calls is a nice concept, but Nurse has shown that things could get messy due to the number of subjective calls in the NBA.