To create a Windows disk image for Nutanix Calm you must first create a Master/Gold Image. Start with a clean Windows install, Nutanix VirtIO drivers, and NGT installed. Next run Sysprep with the OOBE, Generalize, and Shutdown options.
Once the VM is shutdown SSH into a CVM to get the vmdisk path and uuid.
vm.get "<name_of_vm>" include_vmdisk_paths=true
nfs://<CVM IP>/<storage container>/.acropolis/vmdisk/<uuid>
Now you can use the Guest Customization Sysprep function in Nutanix Calm to deploy your Windows VMs.