This event put in a new light the Kherson evacuation done by Russia a few weeks ago where they displaced what was more likely their loyalists all the while they were apparently already preparing this by raising the water level behind the dam itself.
China has identified some of its own dams as an issue in case of conflicts with other nations, mainly the Three Gorges Damn which might affect up to 400m people were it to collapse. Maybe a blatant use of such attacks by another country will force them to also condemn the attack as they certainly don't want the world to view this as a valid option in the future.
I hope for swift action by Nato but I fail to see how this can even be done at this point.
Of course, the usually raised sanction provides more equipment and better equipment but it does not seem sufficient to adequately respond to this Russian terrorist attacks. Maybe it will be enough for the US to send long-range Himars.
At the same time, a forceful reaction from Nato is probably one of the goals of such an attack, Russia is a dying country using its last resources to provoke others as much as it could. They are looking to generate a reaction that would justify all their action in retrospect in the eyes of other dictators and unstable countries and push some to join them against the collective West. So it's very hard to judge how will Nato react to this.