I like your enthusiasm but its actually an oversight of the core issue

Under the current model of grid planning energy is generated as it's needed in real time. Energy is generated to meet demand and then a little more as a backup measure. In nuclear countries like France their power plants take so long to kick in that their backups need to be bigger, as if suddenly power demand spikes way above expected there's nothing they can do (way more nuanced than this but I'm oversimplifying)

If they redirected this excess to any kind of actual application (like car charging stations) then it's no longer insurance against fluctuations in grid networks, but more electrical applications that need power ironically likely leading to even greater fluctuations. It's no longer an excess of its being used.

Unless, you were savvy and setup the charging stations to be 'low priority'. Meaning they only take electricity if the grid has excess. And though this would be convenient for grid planners, the potential for users to charge their car for work and then not have enough power after charging because the grid didn't have any excess, is a bad one.

So overall nah not really lmao the extra power requirements of electric vehicles leads to more energy demand fluctuations which in the current model, makes nuclear power plants even less desireable