Update howto-azure-operator-nexus-prerequisites.md

Author: sushantjrao

articles/operator-nexus/howto-azure-operator-nexus-prerequisites.md

@@ -59,6 +59,7 @@ az provider register --namespace Microsoft.OperationsManagement
 az provider register --namespace Microsoft.ResourceConnector
 az provider register --namespace Microsoft.Resources
 az provider register --namespace Microsoft.Storage
+az provider register --namespace Microsoft.NexusIdentity
 ```
 
 ## EncryptionAtHost feature registration