I do agree wind and solar are cheaper presently. But this is primarily because they're being deployed in the context of supplementing a fossil-fuel backed grid. Provisioning more wind and solar starts becoming much dicier when you start saturating the grid during hours of peak production. In theory, negative electricity prices will prompt people to provision storage and capture the free (cheaper than free!) energy. But in practice, energy storage at grid scale is expensive and there are much better uses for batteries - chiefly in electric vehicles.

Nuclear, on the other hand, is one of the few carbon-free energy sources that is non-intermittent. The only others are geographically limited: hydropower and geothermal power.