Steve Nash says Zion Williamson should have no regrets about his injury at the McDonald's All-American game this week ... telling TMZ Sports it's all part of the game.
Zion -- who's quite possibly the most popular H.S. hoops player since LeBron James -- hurt his right thumb while trying to brace a fall in the 2nd half of the all-star showcase on Wednesday.
We asked Nash if it's too big of a risk for young H.S. prospects to play in meaningless games before getting the chance to cash checks ... and Nash shoots down the idea.
"You're a basketball player ... You have to play every day to be the best you can be and to compete. People get hurt."
It turns out Zion's parents say he's gonna be okay ... but it was a scary incident for the Duke commit.
BTW -- we also talked to Nash about getting picked for the 2018 Basketball Hall of Fame ... and he tells us how he celebrated.