Why nuclear? Because it's cleaner than fossil fuelds but appeases the administration because it isn't wind or solar, which would immediately solve any power generation problems.
You might be tempted to say, since this always comes up, "what about base load?"
FFirst, batteries can solve that problem.
Second, you use a mix of power and when the Sun isn't out (ie night) is when power is cheaper from other sources.
Third, data centers don't really need base power at all. You just run the DC when you have power and don't when you don't. There's precedent for this. Google has a DC in Scandanavia that they shut down a few days a year when it gets too hot, otherwise it's just cooled by ocean water.
What I find most funny about all this is that all these big tech companies are kowtowing to the state in the exact same way they accuse Chinese companies of doing.