I've edited the title to make it more specific and searchable. If your Leaf came with a dual voltage charging cable/EVSE, then you can install just a 240 NEMA 14-50 volt outlet on a dedicated circuit, and use that. The circuit has to be 40 or 50 amps, though - NOT a 30 amp dryer circuit. The reason is that the Nissan dual voltage unit draws the full 27.5 amps that the car can use, and this exceeds the requirement that this kind of device use no more than 80% of a circuit's available amperage. Nissan goofed by not providing either a 24 amp charging cable or at least a setting for that amperage.
If your Leaf came with just the 120 volt charging cable (no Tech Package) then you can get a 240 volt, 16 or 20 amp L-2 EVSE cable for about $200.