Ofcourse it'll be hard, but I do think the circumstances are there. The route is there. There's no GC rider that'll put 3 minutes into him in the ITTs. The main differences will be made on massive, 50 minute + climbs. That's where Nibali shines.But he wasn't flying away from them either.
When was the last time Nibali dropped all of his competitors in a mountain stage in a GT? I can't think of anything after 2016.
The thing with Nibali is that he needs very specific conditions to win a GT at this point of his career. He will be up there, a podium is very likely, but winning will be hard.