Absolutely! Though in practice battery storage tends to be more economical with renewables as the excess is higher (so electricity is cheaper) and storage time is shorter (as upping nuclear baseload would require you to account for differing long-term demand between seasons)
What about nuclear + storage (pumped hydro, batteries) then? That should let you up the baseload a bit right.
Absolutely! Though in practice battery storage tends to be more economical with renewables as the excess is higher (so electricity is cheaper) and storage time is shorter (as upping nuclear baseload would require you to account for differing long-term demand between seasons)