Yeeeeah, Loki's death is complicated but his actual rebirth, not so much! (I originally started with that issue and was figuring there was more going on that I didn't know about, but...nope!)
(ETA: this is not the only time Thor does this - he finally resurrects Odin by hammering on his coffin really hard. The rule seems to be that as long as their soul is around and not actually in Hel's realm, bringing an Asgardian back from the dead is no big deal. Once Hel has 'em it's another story; she doesn't like to let go...)