See this right here is a common belief on Sherdog. Conor landed two solid punches in that fight. One, an uppercut that snapped Floyd's head back and two, a body shot that visibly hurt Floyd to the point that he complained it was low and got a breather (it wasn't low). It's almost as if not only did folks here not watch the fight but they clearly don't watch boxing. Even the heavy hitters at the weight class above (Canelo and GGG) don't one shot KO people, let alone Floyd. He doesn't get hit clean much but when he does he shows no ill effects. Floyd has an absolute granite chin.
Now, look at Conor in MMA. He dropped Nate 3 times, KO'd Aldo with one shot (who had only been briefly dropped once in his career by an absolute rocket of a Mendes right hand), dropped Alvarez 3 in route to a finish, dropped and TKO'd Poirer, and finished a few other folks with punches. He absolutely has stellar power in his left combined with great accuracy.
All that said, Henderson's right is probably the best example of a trump card in the history of MMA. If he can land it he wins. Period. So Henderson.