By putting a higher percentage on nuclear you reduce the need to create storage capabilities. Nuclear should ideally cover a majority of nighttime hours with the rest being handled through solar storage and wind.

Yes this will be more expensive than the current solution which is to fire up the coal plants at night, but some costs are worth it. Maybe this can be handled by battery storage, but no one has done that yet so it is hard to gage the final cost.

I care just a little more about not burning fossil fuels than the cost