Isolate lab enviornment

Hi All,

I have a small query.

I want to create a Esxi Lab in my work place. My ESXI host is has only 1 NIC.

My Requirement is:

1.Want to isolate my lab vms' apart from my company production VLAN to avoid any damage due to learning and test

2.My Lab VMs' needs  to access internet whenever its required only and its should be with NAT using my Physical NIC(my production subnet is small).

How Could I accomplish this. I am using the below version of Esxi.

ESXi version:           

Thanks

Alex