I think in the video you linked, what's being shown is an instance of VCV Rack representing the modules running within the MetaModule, and there's a non-interactive MetaModule faceplate in that rack that you can use to map from the real MetaModule's controls to the virtual knobs of the modules it's running. Which is a pretty cool interface.
But I reckon what the GP is asking is for a real interactive MetaModule within VCV Rack, running the real firmware - i.e. VCV Rack hosts the MetaModule, which hosts VCV Rack, which could presumably host another MetaModule, which could host another VCV Rack ... etc etc.