I agree, especially with respect to batteries. It's not about nuclear vs renewables, it's about nuclear vs batteries. We can probably scale up energy storage to meet the world's baseload needs - but we haven't done that before. It might take a long time, we might hit some dead ends, and it might not end up being as cheap as we hope. But we have seen nuclear power on a large scale so we know what it takes. To be certain we can get zero carbon as soon as possible we should pursue every promising avenue.

Also note that the cost of, for example, solar energy has decreased 94% in the last 35 years because we have (rightly) put lots of resources into research and scaling up production. Meanwhile nuclear investment has been way down for decades. Maybe the cost of nuclear would come down with economies of scale, and newer designs.