Toyota most definitely will not be using NiMH if they ever do make EVs.
NiMH batteries will last the liftetime of the vehicle, if you do not charge the car during hot afternoon hours (the heat is terrible for NiMH) and keep the SOC between 20% and 80%.
NiMH goes about half as far as lithium. And if you want to have that great 10+ years and 100k mile lifespan, you can only utilize about 60% of that range. Lithium, on the other hand, can handle much more drastic variations in SOC, only adding to its range capability.
NiMH is larger and heavier b/c of its lower energy density, only adding to its other problem: lower power density. The Rav4 EV accelerates as quickly as (if not slower) than the Smart.
NiMH should've been powering tens of thousands of EVs, ten years ago.
Lithium is available and far better. Given the choice, why would automakers choose a ten year old technology?
Lithium's only downfall in comparison to NiMH is its unknown calendar life. On that front, only time will tell.