Hi,
When you create a new virtual machine from an ISO file, the default NIC is created, this is because you have not yet installed the VMware tools and the VMXNET3 is not seen.If you want to create virtual machines with the VMXNET3 NIC you have to create a template already with the updates and the VMware Tools installed.
Then before the conversion to Template you change the type of NIC in VMXNET3.
Best regards,
Alessandro Romeo