Please refer following blog post
Migration Paths from v5 Certification to v6 - VMware Education and Certification Blog - VMware Blogs
that's where there's a mention of VCP-NV holder gets Auto migrated to VCP6-NV
so if you manage to Book an appointment for VCPN610, and pass it. then you get VCP-NV
I guess it should auto upgraded to VCP6-NV
still best to check with certificaiton@vmware.com
