Very "open ended" question that !
Do you work in a Nissan dealership currently ?
I suspect you would firstly need to be a fully skilled, qualified and Nissan trained "time served",.. auto mechanic before you were eligible for "Leaf" training.
They most likely have a selection procedure based on past performance and technical aptitude.
Also opportunities will be highly variable depending on where you are located and what the local sales of Leaf's are.
So Cal will have a need for more trained up Leaf Tech's than Darwin (Australia) ! :lol: