Each Nutanix node and block is delivered with a default Starter license, which does not expire. You are not required to register this license on the Nutanix Customer Portal account assigned to you when you purchased your nodes. These licenses are automatically applied whenever you create a cluster, including after you have destroyed a cluster. You do not need to reclaim Starter licenses in this case.
https://portal.nutanix.com/page/documents/details/?targetId=Prism-Central-Guide-Prism-v51:lic-licensing-managing-c.html