With the condition of the players who have recovered such as Di Maria, Chiesa, Dusan and even Pogba of course at this time Juventus' condition is much better than before so they will be able to make it possible to successfully advance to the next round in the Europa League.
Juventus' condition is in contrast to Nantes because it seems they are still not ready to be in this league, especially with their not-so-good condition in the Europa League and Ligue 1.
I do agree that they will be a lot better team than they have been so far, but that still doesn't mean that they will be a better team overall. First we have to see what's going to happen with United and Barcelona game but both of those teams look like a better team than Juventus, and aside from that there are some other teams which have a good chance to win and be better than Juventus as well.
I get that they are doing half decent for now, and they have a good amount of players coming back, but that doesn't suddenly put them on the top of the teams list. I am guessing it is going to be a bit of a trouble in the long run, when they start to face other big name clubs.
For now there are no serious concerns about the opponent they will face. Juventus has a much better advantage compared to Nantes. The real test will come when they are in the round of 16 because maybe they will meet a much stronger team than Nantes. They have to anticipate this to make good preparations. But they also must not underestimate the match that is in front of them.