Nuclear is steerable for renewables, sure. You wouldn’t use nuclear for frequency management (pumped storage, battery and a few - hopefully never used - gas plants manage frequency) but renewables don’t change their output that quickly. You pretty much know what you’re going to get out of renewable resources tomorrow and you certainly know what you’re going to get out in the next four hours. If nuclear was built to support this planning (with molten salt or other heat store) it could be done very economically. Look at how Sweden manage their nuclear output depending on the amount of wind Denmark has to sell them cheaply.