It's a very complex procedure because of NSX & VSAN existence can prevent you to do that. VMware always ecommends that plan and prepare your vSphere Distributed Switches before installing NSX for vSphere.
When you deployed NSX in your environment why you need to migrate a host networking from a DVS to another one?
However, it's not bad to review the following links before start your migration operation:
NSX and vSphere Distributed Switches
vSAN Stretched Cluster Using an NSX-T Backed L3 Network | VMware
https://nielshagoort.com/2016/04/19/stretched-cluster-with-nsx/
