EV CO2 footprints are in the same ballpark as gas cars. It's just environmental procrastination, there's nothing in sight to make two cars per household sustainable. (Or even one for that matter.) Giving subsidies to nuclear plants wouldn't drastically change the picture.
Electric cars have similar CO2 emissions as a Prius on the current US generating mix. Of course, you can drop that to near zero by buying only renewable power (which would cost me about 10% extra if I felt like doing it).
I'm curious as to why you think nuclear wouldn't drastically change the picture, though. Nuclear substitutes nicely for coal on the grid, and coal power is by far the biggest offender here.
To drastically change the picture you need to cut into the demand for fossil fuels. Subsidies for nuclear power and individuals opting for renewable electricity only make incremental increases in electricity supply and indirectly crowding out fossil energy this way is very expensive compared to going at the culprits directly (eg heavily taxing/cap-and-trading co2 and investing the proceeds cleverly to combat climate change).
