No training in the world can mitigate that punch. Unless there was a glitch in the video it was very fast and at almost arms length. If your chin can’t absorb that shot you’re done.
Sure, with the punch coming and the victim unprepared, he’s down for the count.
With training and some sparring practice, you’d see the approach, the expression on his face, the proximity. You’d have your hands and stance where you needed them and you’d be ready to anticipate, block, and if necessary, aim a blow.
I’ve had some fighting experience in my life and some years ago I was caught by surprise and that was enough.