Mendez jumped levels. That's obvious. He had other losses last year that would be crazy to think about him losing this year (Ragusin, Michael McGee x2, Chris Cannon, Latona).
But as far as Nagao goes, I think it's more so a thing where guys figured out his style and coaches had specific gameplans to beat him. I think he has a very unique feel that is hard to figure out the first time around. But, after a season of film, coaches started to figure some things out. Confidence issues MAY have come after losing a few matches to guys that he 'felt' like he should beat. But as far as confidence issues stemming from INSIDE the room, I find that hard to believe. Coaches usually put their starters with guys that are going BOOST their confidence, not diminish it. I doubt Nagao is wrestling Bartlett, Kasak, Davis, etc. I'd be willing to bet he's wrestling back up 125s/133s/141s.