Add note about 3rd party virtualization support

Author: ntrogh

articles/lab-services/concept-nested-virtualization-template-vm.md

@@ -39,6 +39,8 @@ Before setting up a lab with nested virtualization, here are a few things to tak
 
 - Hyper-V client VMs are licensed as independent machines. For information about licensing for Microsoft operation systems and products, see [Microsoft Licensing](https://www.microsoft.com/licensing/default). Check licensing agreements for any other software you use, before installing it on the template VM or client VMs.
 
+- Virtualization applications other than Hyper-V are [*not* supported for nested virtualization](/virtualization/hyper-v-on-windows/user-guide/nested-virtualization#3rd-party-virtualization-apps). This includes any software that requires hardware virtualization extensions.
+
 ## Enable nested virtualization on a template VM
 
 To enable nested virtualiztion on a template VM, you first connect to the template VM with a remote desktop client. Then, you make a number of configuration changes inside the VM.

articles/lab-services/how-to-enable-nested-virtualization-template-vm-ui.md

@@ -16,6 +16,9 @@ Nested virtualization enables you to create a multi-VM environment inside a lab'
 
 This article covers how to set up nested virtualization on a template machine in Azure Lab Services using Windows roles and tools directly.  There are a few things needed to enable a class to use nested virtualization.  The following steps describe how to manually set up an Azure Lab Services machine template with Hyper-V.  Steps are intended for Windows Server 2016 or Windows Server 2019.  
 
+> [!NOTE]
+> Virtualization applications other than Hyper-V are [*not* supported for nested virtualization](/virtualization/hyper-v-on-windows/user-guide/nested-virtualization#3rd-party-virtualization-apps). This includes any software that requires hardware virtualization extensions.
+
 > [!IMPORTANT]
 > Select **Large (nested virtualization)** or **Medium (nested virtualization)** for the virtual machine size when creating the lab.  Nested virtualization will not work otherwise.  
 

articles/lab-services/how-to-enable-nested-virtualization-template-vm-using-script.md

@@ -21,6 +21,9 @@ To enable nested virtualization on the template VM, you first connect to the VM
 - [Enable nested virtualization by using a script](#enable-nested-virtualization-by-using-a-script).
 - [Enable nested virtualization by using Windows tools](#enable-nested-virtualization-by-using-windows-tools).
 
+> [!NOTE]
+> Virtualization applications other than Hyper-V are [*not* supported for nested virtualization](/virtualization/hyper-v-on-windows/user-guide/nested-virtualization#3rd-party-virtualization-apps). This includes any software that requires hardware virtualization extensions.
+
 >[!IMPORTANT]
 >Select **Large (nested virtualization)** or **Medium (nested virtualization)** for the virtual machine size when creating the lab. Nested virtualization will not work otherwise.