This year uefa champions league round of 16 is not tough, the only tough matches in the round of 16 are Barcelona vs Napoli and Atletico Madrid vs Inter Milan. I see Borussia Dortmund winning against PSV because Dortmund is more experienced than PSV in the uefa champions League, and Borussia Dortmund topped the group where clubs like PSG and AC Milan are.
The matches for the round of 16 have not yet started because all matches for the Champions League will resume in mid-February even though many people have made predictions from now on. You may say that Borussia Dortmund is more experienced in the Champions League than PSV, but this season there could be quite different results because PSV is also quite strong this season so Borussia Dortmund cannot be careless with the experience they have.
Although Dortmund has better experience in the Champion League compared to PSV, but I think it still does not fully guarantee for Dortmund to be able to beat PSV . Indeed, Dortmund are in the hell group in the group stage but still, PSG and Milan also have a performance that is not completely stable at that moment. With this factor, then I cannot assume it is entirely possible about Dortmund being better than PSG and Milan.
After all, in this season the fact is that PSV also has very good results in the Eredivisie, because PSV managed to win all its matches in the first half of the season. Indeed, the results of matches in the domestic league cannot be fully used as a benchmark for their performance in the Champion League. But yes, at least with the good results PSV has in the domestic league is likely to make PSV's morale also remain good in the round of 16 against Dortmund later.