you're required to have 18" between a gas furnace and any combustible material. Whether or not the EV charger is considered combustible material, I don't know, but that's the only applicable code I can think of. Just from my gut of being involved with a lot of code stuff, I would say it would probably be frowned on to put it where you are thinking. Seems too close to the furnace.

edit: Just fyi, this is fire code, not electric code. You're probably also going to want to check IRC and IECC, depending on what state you're in.