$switchName = 'nat-switch'
$switchNetworkAdapterName = "vEthernet ($switchName)"
$natGatewayIpAddress = '192.168.5.1'
$natIpPrefixLength = 24
$natNetworkName = 'nat-network'
$natNetworkInternalIPInterfaceAddressPrefix = '192.168.5.0/24'

New-VMSwitch -SwitchName $switchName -SwitchType Internal

Start-Sleep -Seconds 1

$newVirtualSwitch = Get-VMSwitch -Name $switchName

$virtualSwitchNetworkAdapter = Get-NetAdapter -Name $switchNetworkAdapterName

$newVirtualSwitchIfConfig = ($virtualSwitchNetworkAdapter).ifIndex

New-NetIPAddress -IPAddress $natGatewayIpAddress -PrefixLength $natIpPrefixLength -InterfaceIndex $newVirtualSwitchIfConfig

New-NetNat –Name $natNetworkName –InternalIPInterfaceAddressPrefix $natNetworkInternalIPInterfaceAddressPrefix