Hmmm, well the thing is that people aren't really all that creative with either property. With Zombies we always have to have some kind of modern at least pseudo-scientific explanation for them, and there is a constant attempt to show an apocalypse without much in the way of explanation of how things turned out that way except for some occasional scenes of global panic or whatever. It's what I tend to refer to as the "Walking Dead" syndrome nowadays, we are supposed to accept the military was overrun, they even use an abandoned tank as a major setpiece, but it's still beyond me how Zombies are going to defeat a properly fielded modern tank. Likewise response is always either machine guns and maybe choppers, or someone threatening to nuke a city, nothing in between. The point is here that the entire thing is mindless and played out as it exists now, but we've got room for stories in between the lines that get ignored. To make zombies "Fresh" again all someone has to do is go back to the supernatural angle, and limit the environment to a more personal one as opposed to "OMG, they have overrun the world". Even following the current set up, to do something new all you really need is something like oh... "Tanks Vs. Zombies" (dumb name, but the point is there), take something like Roger Zelazny's old "Damnation Alley" idea, and instead have this movie about a few tanks plowing heroically through a small, infected, city in order to get to the cure so the air force doesn't just come in and drop Daisy cutters all over the place... I mean sure, it's pretty obvious (or should be) the tanks are going to win, but a few situations could be contrived to add dramatic tensions, and at least it would be something you haven't seen before.
As far as the Nazis go, they tend to get over used because nowadays it's politically incorrect to have anyone be the bad guys. When they used Russians in the last Indiana Jones movie there was an outcry about it being bigoted. If you use Muslims (despite being at war with them) people get upset, ditto for the Chinese (who also refuse to show movies portraying China in a negative light). This pretty much means you've got THREE basic enemies your allowed to use for global threats, a malevolent corporation, a rogue US government agency, or the Nazis. This makes Nazis (either modern hold outs, or a story set in the past) a go-to villain simply because they don't offend anyone except for maybe the Germans who seem to act like the Japanese in trying to basically forget about it. At the end of the day it doesn't much matter because as your dealing with a Hollywood propaganda-enhanced version of evil in any of those cases, and all of them could theoretically be behind anything. If you want to have people shown fighting against a facist state they live in, you use the rogue government angle (to avoid having it just be "business as usual" in China... one of the reasons we don't set more movies outside of the US), if "they are doing it to make money" then you go with the corporation (which also works for general insanity, since the CEO could be unhinged), with Nazis it tends to mostly come up in the realms of the fantastic since they were really working on the occult, psionics, and various scientific super weapons.
To be honest if you wanted to make the Nazis fresh again, you could always downplay the genocides and such and focus on other aspects. Say if you were to make a World War II supernatural adventure show based around a team of German occultists (which they actually have) hunting down artifacts, fighting monsters, and similar things. The gimmick being that nobody knew about this because the Germans lost and it was all carefully erased. Not all Germans were throwing Jews into concentration camps or whatever, and it would provide a different kind of atmosphere to most similar shows, especially given the popularity of anti-heroes. You don't set out to make these guys all exceptions to the general mould or speak against policies of the time, you just don't mention it since all of that kind of stuff is happening elsewhere while this team focuses on their very specific objectives.... the point here is simply that there were a LOT more things the Nazis were doing other than running around gleefully performing war crimes.
At the same time if you wanted to use the whole "Nazi" thing but mix it up, you can always have the Japanese be behind it, they were even worse than the Nazis. Things like "Unit 731" made many of the worst excesses of the Germans pale in comparison. Have the mad scientists turn out to be Japanese, or the evil organization in modern times be Imperial Japanese hold outs, out to kill pretty much everyone non-Japanese as opposed to Jews, Gypsies, etc... While this could work of course, Japan is a major trade partner, and where we put a lot of major military bases, so we'd probably never do it (again, why we go back to Nazis).