xenforo itself is - no prob there. but from what i gathered from some forums is that addons might cause issues here or there. have no mentions-worthy experience with nginx myself (neither with or without xenforo). so at least the second part above is pure hearsay.
nginx is a lot faster than apache and is able to handle more requests a the same time.
i using nginx many years and also with xenforo (2.2.2) and many different plugins.
nginx is used by many very big sites and has no problems with ssl or urls it self. Maybe if you configure more as needed.
i have to say (just playing around with nginx and xenforo now for a couple weeks on a 'sandbox' server) it sure is faster, less resource intensive as well (it seems) and so far i still have to encounter any serious issues. the few things i struggled with initially got solved within minutes doing a google search. also not xenforo related , rather my config attempts in the beginning.