tlance
Kyrie Hater
Nope, you don't have to be set. You can still be moving and still get a charge call.
Defintely don't have to be set. In fact, defenders rarely are.
The best indicator of block/charge as described to me by college level refs is if the defender takes the contact in the middle of his chest it is a charge. Square contact implies the defender beat him to the spot whether he is moving or not.
On that play, LeBron got to the spot in time, but he did not take the contact squarely because he was still moving his torso to close the gap between he and the other defender.