The technical side isn’t solved with nuclear waste, either. There isn’t a single final storage site in the world. We just started building nuclear plants, without knowing how to actually store that trash so it’s “well sealed”. Nowadays there are a least ideas, investigations and plans but nobody actually created one, moved all their trash there and started using it. But once they do, it’s also not simple. All of the existing trash needs to moved around the respective countries (hopefully nobody signs on the idea to move it between countries) since it’s only in temporary storage, I’d call that far from “well sealed”. There will be literally trains or trucks carrying that shit through neighbourhoods, ifnthey ever actually find their permanant storage.

Also the choice is absolutely not between CO2, greenhouse gases and nuclear waste, that’s just pro-nuclear nonsense. Plus, since when do we trust governments and possibly involved companies to actually find a solution that will not harm anyone? Putting your trust into them to not dump that shit in unsuitable sites is a huge ask. They can’t do that with chemicals, so why would nuclear trash be any different?