Hey there! Apologies, I've had a pretty bad chest cold here so I've kind of been out of commission for a few days so the answer has been a bit delayed.
Cyclical options like Nutrien are hard to buy/sell for this exact reason. Changes in commodity prices due to global events can have a significant impact on earnings. We've witnessed it many times with oil and gas. However, I think commodity headwinds will definitely be here for a few years, and I think Nutrien is going to benefit from them. We're likely to see a big uptick in 2022 earnings and maybe even 2023 as well.
If I owned Nutrien right now, I'd most certainly be holding. If I wanted to buy, I'd be a buyer, but maybe a bit cautious just knowing that headlines could send this stock up or down by a large degree. For example, as you mentioned if sanctions are lifted and Putin opens up grain and fertilizer exports, we could see a dip in commodity prices, and as such Nutrien could face some earnings downgrades and volatility in price.