You're correct that one should factor in the cost of storage if one wants to considers renewables as an alternative to nuclear for providing base load power.

Hydro plants can adjust output but it changes river levels and flows with environmental consequences.

I imagine nuclear plants could use control rods to generate less power if they had to?

Or if you have the nuclear power because you need it anyway in case it isn’t sunny/windy but it is a sunny and windy day how do you decide if solar/wind or nuclear should be curtailed? Both have near zero marginal cost.

Play with the assumptions and see for yourself.

What the hell are you talking about.

Solar being cheaper than nuclear makes it a foregone conclusion for daytime electricity supply.

However the direct comparison you were making in the first paragraph of your original post between nuclear price and solar price is nonsensical because they're not in direct competition with each other. Nuclear satisfies a slightly different use case to solar.

Nuclear instead is in direct competition with sources that are capable of providing base load power such as gas and solar+storage. The only meaningful price comparison is between nuclear and these other sources, since we need to decide if the stack is going to be solar+storage, solar+nuclear, etc.

Comparing solar prices directly to nuclear prices without considering the whole stack is just a meaningless comparison.