Nuclear (and everything else) has the same problem, demand is not constant. You want to cover the yearly peak even if its a 1 in a hundred year snowstorm or heatwave thats causing it.

So you can either build 10x as many nuclear plants and run them at .1 capacity most of the time or build 5x as many and use some of the surplus energy to create stored power like hydrogen.

Doing either of those things with renewables will be massively cheaper than nuclear.

There doesn't seem to be anyone who is actually enthusiastic about nuclear, only people who are misinformed about renewables because their news sources have been trying to prop up fossil fuel interests for the last two decades.