Is e-Nomination of beneficiary Legal

Yes, e-nomination is a legal contract between you and your beneficiary. It can be used by your beneficiary to claim the money/assets you left behind. 

e-Nomination is like you are writing your Will, but it is much simpler and straight forward. the bottomline is, you do not need anyone's permission to assign a beneficiary to your asset or to eNominate. It is your right and no one can dispute its legality. 

Imagine if you give money to someone and they sign an IOU (I owe you), that document is legal. So is eNomination. It is a contract that is legally binding and can be used by your beneficiary to file a claim when the time comes.