VMware has released vSphere vCenter 6.5a, ESXi 6.5a and NSX for vSphere 6.3.
vCenter 6.5a and ESXi 6.5a is needed for NSX 6.3. They also contains bug fixes.
See release notes for vCenter 6.5a here: http://pubs.vmware.com/Release_Notes/en/vsphere/65/vsphere-vcenter-server-650a-release-notes.html
See release notes for ESXi 6.5a here: http://pubs.vmware.com/Release_Notes/en/vsphere/65/vsphere-esxi-650a-release-notes.html
NSX for vSphere 6.3 also has a lot of new feature and enhancements. See the full release notes here: http://pubs.vmware.com/Release_Notes/en/nsx/6.3.0/releasenotes_nsx_vsphere_630.html
NSX for vSphere 6.3 is not compliant with vRealize Network Insight 3.2. vRealize Network insight 3.3 released with support.