This question resolves to YES if Niemann is kicked out of the U.S. chess championship, or otherwise disqualified. (For instance "you can play but you can't place or win prizes" would result in YES.)

It resolves NO if Niemann plays all his games normally, or withdraws voluntarily.

If there is overwhelming evidence that the withdrawal was done under an extreme threat ("withdraw or we kick you out"), then this'll resolve YES, since that's not really voluntary.