PyNSXv offers a Python-based API and interface to control NSX. You just need to offer the NSX Manager and the vCenter IP and credentials as well as names for the vCenter data center, edge data store, and edge cluster for the gateways. A complete NSX API Guide can be found at https://pubs.vmware.com/NSX-6/topic/com.vmware.ICbase/PDF/nsx_604_api.pdf and NSX for vSphere API Guide can be found at https://docs.vmware.com/en/Vmware-NSX-for-vSphere/6.3/nsx_63_api.pdf.