There are at least two wholly separate issues here. One is the technology. They have examples of future technology and they have hundreds of technically skilled people who know how to maintain it and repair it.
The Nimitz probably doesn’t have people who are specialists in materials creation/design. That is, there will be lots of stuff that can’t be replicated because the materials to build them don’t exist in the 40s. I’m not expert enough in the science to say how quickly those materials could be developed given actual working examples for examination. Some things, like for example guided missiles, were already in the concept stage early in the war, and while they may not have been able to build a replica Tomahawk or a replica Harpoon, they could probably develop a reasonably effective similar weapon (bigger, slower, shorter-ranged) that would be very useful.
Aside from the technology, there is an issue of the individual Nimitz crew members and their knowledge of history. That would be a crapshoot. Elendil’s Heir made this comment:
That’s one possibility that might be true. But what if none of the crew happen to know the names of the specific Soviet spies? Ok, maybe they know the Rosenbergs, but they don’t remember the names of all the others who stole nuclear secrets. Hell, the only name I remember for sure is Klaus Fuchs, and I’ve read books on the subject.
My point is that the crew can say definitively that there WERE in fact active Soviet spies in government, but may or may not be able to ID them. That could end up making the Red Scare even worse, because no one on either side will want to step back from spy hunting when the benefactors from the future assure them the spies are real, just not as many as people thought.
It’s this kind of stuff that maybe would have led to a Nixon victory over Kennedy in 1960. Or to J Edgar Hoover building a more powerful and intrusive FBI than we can even imagine.
So I am not one to think that this gift from the future would be all rose petals and sunshine, because the knowledge of how the future plays out will be incomplete at best, and maybe even wrong in many cases. And of course we have to assume that changing the course of events based on this knowledge will make history diverge ever further from what we know of it. Perhaps we get all the nuclear spies, pat ourselves on the back and move on. Well, maybe the Soviets mount a new aggressive campaign to replace the spies they lost, a campaign that didn’t happen in the past the Nimitz crew was familiar with.
I think an event like this will be subject to some law of diminishing returns. The more knowledge they have and the more they bend the shape of government, the military and society to deal with it, the more history diverges what what they knew and the less relevant their knowledge becomes.
If they (Roosevelt and Churchill) want these guy to be the most powerful weapon that can be, they’d have to treat them like the Ultra secret. No one but a very small circle knows where the information comes from, and the information is acted in indirectly, with plausible reasons developed as to how it might have happened without access to the enemy’s plans and intentions.
But if you make Nimitz the flagship of the fleet and send it storming all over the world to destroy our enemies in combat, that’s not gonna happen.