it actually is a choice between nuclear and PV, because base load supply is an obsolete concept. Because actually nuclear is terrible in a grid increasingly full of nearly-free variable sources (solar&wind). The nukes need to stay at 100% all the time selling their power at a high fixed price to have any remote chance of being economical. Cheap variables push nuke's expensive power off the grid during the day, and increasingly into the evenings with batteries. This is unavoidable in an open energy market, and is fatal to the economics of nuclear. You cannot make them work without massive state subsidies.

Gas is far better suited economically to backstop a variable grid. I wish it werent true, because i dont hate nukes, but it is just economics.

I will also point out that california is down to 25% fossil sourced power in 2025, from 45% in 2022. Due to renewables and batteries, and there's far more coming. The amount left to backstop on gas in a few years could plausibly be 10%! which is amazing.