This line:
$newNodeUri = New-SwisObject $swis –EntityType "Orion.Nodes" –Properties $newNodeProps
Should be this:
$newNodeUri = New-SwisObject $swis -EntityType "Orion.Nodes" -Properties $newNodeProps
Those look almost identical, but the - character in -EntityType and -Properties has been changed from a regular hyphen to some kind of typographic dash character. PowerShell doesn't like it.