Nuclear power including disasters like Chernobyl kill less people per GWh than normal operation of coal plants. Shutting down nuclear plants which get replaced with fossil plants results in both less immediate safety (even if you'd expect the next Chernobyl to be incoming here) and more environmental harm. Heck, even considering specific aspects like cancer and radioactivity, coal plants cause more cancer per GWh than nuclear including Chernobyl, and coal plants release more radiation (in fly ash that then lands on surface and/or gets breathed in) per GWh than nuclear plants including their leaks.
Your argument is a common misconception which is doing a lot of real harm to our world - while the perception is that nuclear is not safe and expensive to clean up, the reality is that fossil fuels are even less safe and even more expensive to clean up - I mean, we can't really figure out a reasonable way to clean up the greenhouse gas effects of historical fossil plants.
Like, I'm not saying that nuclear is free from side-effects, but the point is that burning fossil fuels for electricity is so extremely dirty in their normal operation that they overshadow any and all of the nuclear risks. If the expected result is that the gap will be filled with coal, then reducing nuclear power is both increasing direct risks to local people and also harming the environment; it's literally all drawbacks with no reasonable benefit.