The document says "generation". I though Germany imported a lot of their electricity. I can't tell if these numbers include the source of the imported power.
I'm assuming that's still the case for last year or it would be bigger news. I did see one article fretting that they might turn into a net importer later in the decade.
Image of net export (2023) by month: https://ibb.co/jDkg9sF.
You can query and visualize these data on the official site of the Bundesnetzagentur (Federal Network Agency): https://www.smard.de/home/marktdaten. It's a capable tool, you should check it out. Once using it I realized that news reports cannot replace looking at the time series data.
1) it's cheaper to use excess wind and solar from neighbouring countries which is the vast majority of its imports. Prices in Germany have gone down dramatically since the nuclear shutdown
2) it's better for the environment
So it's basically a win win and far away from disastrous. What is disastrous is when a quarter of your nuclear fleet goes offline unexpectedly and you need to import electricity in the middle of the biggest energy crisis of the last 50 years. And you need to nationalize the electricity company because it made a hole of 20 billion in a single year.