When someone in academia says nature paper they are referring to a publication in Nature or one of its many divisions. I would be pleasantly surprised if leronlimab appeared in Nature because a cornerstone publication of science and academia. Laymen get nature in their mailbox and alongside Cell and Science it's one of the hardest journals to get into. That's why I sort of doubt it unless Nature is doing an article based entirely on covid treatments. It's possible, who knows but this is a long shot.

Nature is so ubiquitous in the field that when you're talking about some technique or theory and you say 'the nature paper' others generally know the paper you are referring to because they are the best of the best.