Hi  Yes, you can change easily from local datastore to a NFS export.  You would need to stop insightIQ services, copy over the datastore to isilon, start the insightIQ services again and finally point InsightIQ to use the new datastore on isilon.   The new version of insightIQ should support exports to CSV files.
Previously when I was using the datastore localy on a VM, I was able to keep the old one while I'm validating the new one . Is this possible when I migrate from VM to NFS export. I mean, if I am using NFS instead of local to the VM, will this change something for the migration?  The second questions I had was, is it possible to download the file system reports? I can view them online, is it possible to download them like I can download Performance reports?
Importing data store in InsightIQ