If you have filled the details on nmat.nmims.edu before completing the NMAT by GMAC exam registration, you would have received an email to complete the registration process for NMAT by GMAC.
On clicking this email, you are directed to mba.com to enter your password and complete account creation.
You can use your email id and password to log-in on mba.com/nmat to access your dashboard and continue with your registration journey.
Please check your SPAM/JUNK folder for this email, if you have not received this email then, enter your email address used at the time of registration initiation at NMIMS at the link given below to re-trigger the email to complete NMAT by GMAC registration process.
https://www.mba.com/service/nmat-resend-registration-email