Not sure, but I take the test and check. There some things will be helpful. When you create the AKS and enable the virtual nodes. There something specific come out in the AKS property different with disabling:

I also find it can be set in the Azure Template of AKS. But I cannot find where it can be set in the Terraform and it just shows like this:

A addon_profile block supports the following:

http_application_routing - (Optional) A http_application_routing block.

oms_agent - (Optional) A oms_agent block. For more details, please visit How to onboard Azure Monitor for containers.

So I think you could not create AKS with virtual nodes through Terraform. Maybe the reason is that the AKS virtual nodes just in the preview version. But I'm not really sure. Hope this will help you.