Or run on nuclear batteries...
Not sure if this was serious or sarcastic, but hopefully you are aware that the power output of those nuclear batteries is miniscule. Their applications are not high power devices such as vehicles, but rather very low power devices where changing the battery is impractical (i.e. satellites and spacecraft)
Anyway, back to the topic at hand: EV charging during special events such as the eclipse:
The same thing happened during the last US eclipse in 2017, and it's not limited to EVs: gas stations and traffic in general experience unprecedented demand during these kinds of events. Hopefully the lesson was learned, but it's guaranteed to happen again whenever these kinds of events occur (fortunately they are very rare).
I traveled to northern NY to see the eclipse. My strategy was to make sure I arrived prior to the day of and left after the day of. And even then, I made sure that I was topped off beforehand so that I could get as far away from the path of totality before needing to charge. I recommended the same to my son who drove a gas car: fill up on the way up and don't count on being able to fill up right after the eclipse.
Perhaps this was a single day trip in the case of the OP, but even in that case I would have left early enough to charge up a few hours prior to the eclipse (even if I had to sit at an L2 charger for a few hours), anticipating long lines even then, so that after the eclipse I would not need to stop and charge until well away from the path (and just for purely traffic congestion reasons, I would probably not leave right away anyway).