They have not started to do it. No nuclear power plant has been constructed for them. Nor have any even started construction. The article you linked to is purchase of power from an existing nuclear plant. This would be a fine precedent if one can build additional power plants for free, with all construction costs sunk. But the Nuclear Fairy is not available to wave her magic wand and present us with such free power plants.

That article is about Amazon buying electricity from a 40+ year old nuclear plant[1] which will operate for another 20 or so years.

Hardly what one could call financing the construction of new nuclear power plants.

[1]: https://en.wikipedia.org/wiki/Susquehanna_Steam_Electric_Sta...

Existing nuclear power is cheap enough to be viable in some locales. In others huge subsidies are being pushed through.

The article talks about new nuclear power plants.

Neither of those companies are even close to breaking ground on any new nuclear power plant.