PowerShell is interpreting the comma as an array, and as such is passing a collection object instead of a string… just add quotes.
10.58.88.61 [0:45]≥ Set-NaOption -OptionName cifs.wins_servers -OptionValue 10.58.88.21,10.58.88.22
Set-NaOption : Cannot convert 'System.Object[]' to the type 'System.String' required by parameter 'OptionValue'.
Specified method is not supported.
10.58.88.61 [0:46]≥ Set-NaOption -OptionName cifs.wins_servers -OptionValue "10.58.88.21,10.58.88.22"
ClusterConstraint Name Value
----------------- ---- -----
none cifs.wins_servers 10.58.88.21,10.58.88.22