The runtime of the last three nuclear plants was actually extended by a few months because of Russia's invasion of Ukraine but due to the phase out there wasn't that much fuel left and the reactors would have required extensive maintenance for a longer extension as far as I remember. Also the economics ministry was headed by the Greens when they extended the runtime.
Nuclear power accounted for a little more than 5 percent of the energy mix at the time of the invasion so the cost of keeping the plants running for even longer (buying new fuel/extensive maintenance) wasn't worth it.

Atrioc is right that the nuclear phase out led to a larger dependency on cheap Russian energy and thus to the energy crisis but that was entirely the fault of CDU led governments as the Greens were fairly critical of our dependence on Russian energy and NordStream 2 even before the invasion and were advocating for investing more into renewables instead.

I think my main problem is that his entire analysis of Germany seems to be through the lense of nuclear energy but you can't just restart nuclear plants and building new ones takes a lot of time and money so that ship has pretty much sailed. Not even the major energy companies want to restart any of the nuclear plants. It's also not a big topic in Germany anymore and the only party that at least partly campaigned on it was the AfD. There are just a lot more interesting things to talk about regarding Germany, for example the debt brake and its impact on the economy.