From 1: The total number of deaths, including future deaths, is highly controversial, and estimates range from "up to" 4,000 (by a team of over 100 scientists[9][3]) to the Union of Concerned Scientists estimate is approximately 27,000 based on the LNT model[10], to 93,000—200,000 (by Greenpeace[11]). Chernobyl: Consequences of the Catastrophe for People and the Environment, published by the Annals of the New York Academy of Sciences, but without NYAS explicit approval,[12][Notes 1] is a 2007 Russian publication that concludes that there were 985,000 premature deaths as a result of the radioactivity released.[13]

From 3: It has been reported that 90,000 - 230,000 people were killed as a result of the dam breaking.

I don't see your point

The problem with trotting out the Banqiao Dam as proof of the dangers of hydroelectric is that it was a dual-purpose dam built to prevent downstream flooding as well as providing power, and it failed due to mismanagement of the flood control aspect. So even if nuclear power had existed at the time, and even if the idea of building a nuclear power plant with the same quality of engineering used in the dam wasn't a utterly terrifying idea that would make Chernobyl look safe, not using hydroelectic power wouldn't have solved the problem. The dam would still have been built and those hundred thousand people would still have died due to dam failure, all that would changed is that nuclear proponents couldn't point to their deaths as proof nuclear is the safer option.