When you upgrade from vCloud Networking and Security to NSX, your existing license is converted to a NSX for vShield Endpoint license.
Starting in NSX 6.2.3, the default license upon install will be NSX for vShield Endpoint. This license enables use of NSX for deploying and managing vShield Endpoint for anti-virus offload capability only, and has hard enforcement to restrict usage of VXLAN, firewall, and Edge services, by blocking host preparation and creation of NSX Edges.
If you have already have vCloud Networking and Security features deployed, including prepared hosts, virtual wires, vShield App, or vShield Edge, they will continue to function, but you cannot upgrade them to NSX, and you cannot make any changes to them.
If you need other NSX features, including logical switches, logical routers, Distributed Firewall, or NSX Edge, you must either purchase an NSX license to use these features, or request an evaluation license for short-term evaluation of the features.
See the NSX License FAQ https://www.vmware.com/files/pdf/products/nsx/vmware-nsx-editions-faq.pdf