This was just approved by unanimous decision at the board of governors meeting the other day. Coach Challenges have been something that the G-League has allowed for the last 2 seasons and the NBA will adopt this year on a trial basis. It has also been added to this year's summer league play as well.
Here is some more info on it, with a link to the article I pulled the quote from below....
https://www.espn.com/nba/story/_/id/27157373/nba-approves-use-coach-challenge-19-20
Here is some more info on it, with a link to the article I pulled the quote from below....
Teams can use one challenge per game regardless of whether it is successful, and it can be utilized to question a call in a variety of scenarios, including a personal foul, an out-of-bounds call, goaltending or basket interference. The challenge can be used at any point during the game. However, in the final two minutes of the fourth quarter or overtime, any out of bounds, goaltending or basket-interference calls will be automatically triggered for review and are not challengeable.
To challenge a play, a team must have a timeout and call one after the play, and then its coach must twirl his finger toward the referees to signal for the challenge. If a team doesn't have a timeout and attempts to challenge a play, it will be charged a technical foul and no challenge will occur. There must be clear and conclusive visual evidence to overturn a call.
https://www.espn.com/nba/story/_/id/27157373/nba-approves-use-coach-challenge-19-20