There doesn't appear to any evidence of nuclear docs. When Trump denied having any nuclear docs that was in response to news outlets floating that idea. That said, if Trump was in possession of classified intel, then he is no longer fit to be POTUS.
Trump is an odd bird. Why would a guy who was so hostile and dismissive of the intel community interested in stealing classified documents? Furthermore, what did he intend to do with those docs? Blackmail - an who would he blackmail. Hand them over to his pal Putin? Just hang on to them like an Ace up his sleeve?
I do find it hard to believe that this is some sort of "liberal conspiracy" to keep Trump out of office. Assuming this does torpedo Trump's opportunity to recapture the WH, we'll end up with DeSantis instead and he's made his name by being "more Trump than Trump." I seriously doubt that is a trade that the Dems would find palatable. As a matter of fact, I think Biden's chances vs Trump are better than vs DeSantis.