You're comparing the power of kicks versus the power of punches. And I'm actually in the process of rewatching the fight. Here, it looks like Thompson is setting the headkicks (two) up with constant leg kicks. He actually threw more leg kicks than he did any other strike. I've noticed none to the body like you're saying here.
Anyway, Conor dropped Nate multiple times with his punches. Thompson had issues landing with his hands, and did most of his damage with kicks on the outside. Conor has significantly more powerful hands. Use the entire fight next time instead of a gif.