There's not a 'baseload problem', there's a 'supply meeting demand problem'. And nuclear and renewables are not a good combination to solve that problem, because they don't complement each other at all: what both would need to efficiently supply the grid is either lots of storage or highly dispatchable cheap generation. The former is being developed and the latter exists but is still fossil fuels. The other option is massive overbuilding, which is far more doable with renewables because they're so cheap.