A Leaf will not hit 100 easily, short of freefall.
It's speed limited to IIRC 93mph, which is simple factor of the electric motor's top limited RPM and the size of the tires. [I actually believe it's actually 90, with the typical speedo adjustment for liability purposes.] Math says 90ish. Nissan says 90's. One guy on a Dyno said 97. Reverse is electronically limited to 25 :)
Here's the details:
On level ground, about 94mph indicated.
The motor is turning about 10,300 RPM divided by a 7.8 reduction gear box is 1320 RPM of the wheels, which are about 23 inches in diameter.
23 * pi = 72.25 inches multiplied by 1320 = 95,378 inches per minute multiplied by 60 minutes equals 5,722,720 inches per mile divided by 12 equals 476,893 feet per hour divided by 5280 equals 90.3 miles per hour ground speed, which is about 92-93 indicated speed.
Too much rounding. The gear ratio is actual above 7.8, but I don't remember off the top of my head and the tire may be slightly larger. Motor speed is slightly above 10,300 RPM also.