What? Be more clear please.
You have email?
If you do it's easy, just go to the question mark next to the login and enter you email. They'll send you a temporary pass or a link to reset your pass.
If you don't have email...
You're in some deep shit unless you can somehow prove that you purchased NX on that account; hence the account is yours. But this only works if you used a credit card / paypal.