Try like this
$esxName = 'MyEsx'
$vssName = 'MySwitch'
$pgName = 'MyPG'
$ipAddr = '192.168.1.1'
$ipMask = '255.255.255.0'
$esx = Get-VMHost -Name $esxName
$vmk = New-VMHostNetworkAdapter -VMHost $esx -PortGroup $pgName -IP $ipAddr -SubnetMask $ipMask -VirtualSwitch $vssName
$vnicMgr = Get-View -Id $esx.ExtensionData.ConfigManager.VirtualNicManager
$vnicMgr.SelectVnicForNicType('vSphereProvisioning',$vmk.Name)