This is a false dichotomy. Nuclear powerplants should not have been stopped. See also: https://news.ycombinator.com/item?id=26603464.
a) Coal did not replace nuclear power
b) Coal was reduced during a policy to shut down nuclear power
c) The policy to shut down nuclear power has nothing to do with coal
The first two are facts you can see in the data. The third one is a matter of simple policy. If it were up to me I would have replaced this policy with. “Nuclear power will be shut down as well as all coal power plants”. The data seems to suggest this is possible.
Looking at different energy markets whether they decided to keep their nuclear power plants (like USA) or to do away with them (like Germany) coal is down everywhere. Nuclear policy seems completely irrelevant to coal usage. What seems relevant is renewable policy and coal policy. Countries which have a policy to reduce coal do so faster, countries that have a green energy policy replace coal with green energy, and countries that don’t (like USA) replace coal with gas.
From the data, what I can gather, is that nuclear policy is simply a decision about country’s willingness to keep operating these plants. Germany didn’t want to so they got rid of theirs. If a country wants to get rid of coal, they do so with a different policy. Alas Germany has a renewable policy, so you see that the nuclear power was replaced with wind + solar. And now that the nuclear plants are all gone, we shall see coal increasingly being replaced by these two power sources in the coming years.
Between 2021 and 2022 Germany's share of electricity from Nuclear declined from 12.6 to 6.3%, coal increased from 30.2 to 33.3% [0]
In a hypothetical scenario where Germany didn't reduce nuclear generating capacity what do you think is the likeliest amount of electricity generated from coal?
a. higher than 33.3%
b. lower than 33.3%
If you think that answer is (b) than decision to shut down nuclear did indeed increase coal usage as compared to hypothetical 2022 with nuclear not closed
If you instead think that answer is (a) I would be interested in hearing the reasoning.
[0] https://www.destatis.de/EN/Press/2023/03/PE23_090_43312.html