It should be possible to do the electrical modifications and additions now, for a 2010 tax credit, wiring to a 240v socket (in a "junction box") on a 40-amp dual breaker (**), putting the socket in-service (completely inspected and ready to use) now, for plug-in charging. Label it "EV Charging Only" and take a picture of it. Most likely, the costs of doing this qualify for the EVSE Tax Credit, I suspect.
Then plug-in (or possibly "mount") any "new" L2 EVSE later, when it beomes available.
(**) I would include dual 20-amp breakers for twin 120v duplex sockets (one on each 120v "phase"). This will be for the initial (and later, when needed) Level 1 charging, to be used with the Nissan "included" EVSE, if one needs to specify the EVSE type that one intends to use.
It will also provide for convenient testing of "Two-120v-makes-240v" adapter cords.