Currently you cannot have 2 NIS domains on OneFS.  This includes 7.0.1.x.  The functionality to support multiple authentication providers is currently available only for Active Directory, file and local providers.  Support for NIS and LDAP authentication in zones other than the System zone will come in maintenance releases.
Inside a Isilon you can have different clusters, can you have 2 different NIS domains in one frame?  Using smartconnect? 
Isilon NIS