One still needs a reliable baseload source, whether it be coal, gas or nuclear. From my previous link, here's a quote regarding the UK situation:
“Using gas as a backup is an expensive solution. So, anybody who is constructing an energy system needs to think not just that we need to reach net zero, but how do we manage that energy system so that it’s reliable? And that means one needs energy storage but also reliable baseload generation.“
In the UK context, you would need something like 40% energy baseload, and nuclear could do that.”
