Batteries cannot sustain the electricity consumption of a whole nation. Maybe in many years, but right now, no sign that it can, whereas plant can
(And I'm saying this as someone who actually likes nuclear, thinks the public perception of the danger is over-stated, and who thinks everyone should have build a lot more reactors decades ago).
I'm expecting most batteries (worldwide) to be used for cars, with bi-directional power so they can function that way (for grid storage) when plugged in. That doesn't say much about what any specific country will do, and as Texas demonstrates, US states can have their own independent energy policies.