(Not financial advice. Stock up on iodine. Etc.).
I was looking at this issue -- there does seem to be some irrationality here. (For example, I think the probability of "will there be a nuclear test before the end of October" should have decayed as the end of October approached, and I think it decayed much more slowly than it should have.) I was trying to think of a way to make this arbitrageable and I came up with the following...
https://manifold.markets/Boklam/if-no-nuclear-weapon-is-detonated-i
So if you're confident you know how people are going to be irrational, go make some M$ :)
Well, it's not arbitrage because many people including myself are predicting it is much likelier to happen sooner rather than later. Some of the probabilities are ridiculous and I've been profiting from correcting them where I could, but I think it is absolutely correct that the probability for 2023 is not much higher than for 2022.