Redirection to 'NUL' failed: FileStream will not open Win32 devices

nul is batch syntax. In PowerShell you can use $null instead, as Mathias R. Jessen pointed out in his comment:

choco install swig > $null

Other options are piping into the Out-Null cmdlet, collecting the output in a variable, or casting it to void:

choco install swig | Out-Null$dummy = choco install swig[void](choco install swig)

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