fnature just as TheBobkin states, you can absolutely replace a failed 3rd node in a 3 node vSAN Cluster.
If you only need to rebuild the 3rd node, when you reinstall ESXi, you'll see an asterisk beside each of the currently consumed/used for vSAN disks.
When the host is reinstalled, and all networking has been restored (vSAN VMkernel interface configured), the disk groups will be seen again.
If you replace the failed node with a net new (not used in the cluster before) node, once ESXi is installed, added to the cluster, and networking (vSAN VMkernel interface) added, you'll need to create any new disk groups.
When either of the above are performed, I'd also suggest invoking a "Repair Objects Immediately" operation from the vSAN Health Check UI.
Can't really speak to Nutanix, as this is a VMware community.