Coal-fired power generation also fell: Lignite-fired power plants generated about 41.2 TWh, a sharp decline of 21 percent from 2022 (52.1 TWh). Net production from coal-fired power plants also decreased by 23 percent, from 26.2 TWh in 2022 down to 20.1 TWh in 2023.
Energy from coal production fed to the grid got to 33% in 2022 from 30% in 2021 according to the Federal Statistical Office of Germany (+8.6% YoY)
It’s not very representative to compare just two data points. If you look at a larger time window you can see that black coal is declining and brown coal is more or less constant https://www.energie.de/et/news-detailansicht/nsctrl/detail/News/stromerzeugung-rueckblick-auf-den-energiemix-seit-1990-zeigt-die-risiken-uebergrosser-dynamik
And most of that was to compensate the lack of french export to the European grid and not because Germany shut down nuclear.
Look at 2023 data for example.
https://www.ise.fraunhofer.de/en/press-media/press-releases/2023/german-net-power-generation-in-first-half-of-2023-renewable-energy-share-of-57-percent.html#:~:text=Coal-fired power generation also,to 20.1 TWh in 2023.