I imagine data centers make the best economic sense when they can run full tilt 24/7. You’ll double your payoff time if you can only run work when the sun shines.
I also think you would need more than 24 hours battery. You have to prepare for freak weather events that reduce system capacity.
I also wonder what time horizon we are talking. solar and batteries presumably have to be replaced more often than nuclear.
In general, yes. Not really in the context of utility generation for a DC, though. A DC should have onsite backup generation, at least to supply critical loads. If your contracted utility PV + storage runs out, and there's no spare grid capacity available (or it's too expensive) you can switch to onsite power for the duration. The capex for backup power is already required, so you're just looking at additional spending for fuel, maybe maintenance if the situation requires enough hours on backup.
Civilian nuclear reactors replace fuel gradually over 3 to 6 years typically. 20 year old solar panels work now. New solar panels are expected to work over 30 years. Utility scale lithium ion batteries are expected to last 10 to 15 years.
[1] https://www.lazard.com/media/5tlbhyla/lazards-lcoeplus-june-...