Vmware-iso build by default export the VM in to VMX format instead it used VMWare's ovftool to export the VMWare build to OVA/OVF format.
Add this post-processor section in packer template
"post-processors": [{
"type": "ovftool",
"format": "ova|ovf",
"remote_host": "<esxi-host>",
"remote_username": "<esxi-user>",
"remote_password": "<esxi-password>",
"keep_input_artifact": true|false,
"vm_name": "<vm-name>",
"target": "<target-file-name or target-dir-name>"
}]
TODO.