set interface method question

[PetruGarstea]

Greetings,
I am unable to figure out on how to set the NAT network interface for the following pf rule

nat on ${NIC} inet from any to any -> (${NIC}0) round-robin

nat rule code snippet

	var natRule pf.Rule
	natRule.SetAction(pf.ActionNAT)
	natRule.SetDirection(pf.DirectionOut)
	natRule.SetProtocol(pf.ProtocolAny)
	natRule.SetState(pf.StateKeep)
	natRule.SetQuick(true)
	natRule.SetAddressFamily(pf.AddressFamilyInet)
	_ = natRule.ParseDestination("any", "0:65535", false)
        _ = natRule.ParseSource("any", "0:65535", false)

At this moment the library handles the rule as the bellow output, and the network interface part is missing, looking forward to finding the correct method that addresses this issue.
nat out quick inet from 0.0.0.0/32 port 0:65535 to 0.0.0.0/32 port 0:65535 keep state

Thanks,
Petru