Nathan didn't skate at 2016 Worlds. In fact, neither did Jason - all three men who were at 2016 Worlds have since retired (Adam, Max, and Grant), and all three had excellent skates. In fact, all three finished inside the top 10, and it was only some bodgy maths (unfortunately, Adam's 6 + Max's 8 added up to 14 instead of the 13 they needed) cost the US men the third spot. There was also some dubious judging involved (some very generous scoring for Uno and Chan's error-riddled splatfests).Nathan has been carrying USFS since 2016 season when he scored the highest score for a US man ever, winning against the big guys then, and we finally got back 3 spots at Worlds.
In 2017, Nathan finished sixth, and Jason seventh, which was what earned three spots for the Olympics. Hardly "carrying on his back".
Even in 2018, Nathan's performance would have been meaningless had Max not had one of the best performances ever by a third alternate.
If you will recall, Nathan finished third at US Nationals, behind Adam and Max who were in the wrong order, and then injured himself at the exhibition.