The usecase of "cloud provider buys power plant to power data center" does not exist: All current power plants are completely unsuitable as single power source for a data center because uptime/reliability is way lower than what you would need; decoupling datacenters from the grid is just a losing move, which is why no credible operator is even trying.
Are we gonna see more vertical integration between power generation/datacenters operation in the future? Maybe. But I'm very confident that we're not gonna see datacenters "leave the electrical grid" to be powered directly by nuclear plants, not now and not within 30 years either.