If you're starting to get your hands dirty with NSX and want to automate some operations using vCenter Orchestrator (vCO), there's now a plugin for it that's been released into the community by Christophe Decanini (who writes on the vCOTeam blog and works for VMware).
It's not a traditional plugin for vCenter Orchestrator in the same way that there are plugins for vCenter / vCAC / Infoblox etc. Instead it's built on the Dynamic Types plugin that was launched with version 5.5 Update 1 of vCO.
The goal of the plugin is to create the ability to offer NSX “as-a-service” operations as catalog items within vCAC. The creation and manipulation of security groups and policies along with the ability to associate VMs with these objects can all be offered as options for users to select within the vCAC catalog using this plugin.
If you're not using vCAC then the plugin could still be used within your own workflows.
The plugin was released on the VMware Communities site yesterday.