chown/chmod does not work with NS8 because ACLs are stored inside an extended attribute: user.NTACL. The contents of that attribute are difficult to administrate with Linux commands because are encoded as Samba likes. You could check commands like smbcacls or samba-tool ntacl set; the best tools are provided by Windows IMO.
However it’s important that ownership of files and dirs is mapped to the container’s root:users uid and gid, that is what Samba expect to write files and dirs correctly, so do not change them!
What NS8 can do from UI is a recursive reset of ACLs to original settings. Bear in mind that members of Domain Admins are always granted full privileges.
I think you can enable that setting as Markus pointed out with a per-share registry entry. As alternative, using a Windows client, set the appropriate ACL bit to allow running a program (by default only read/write permissions are granted for security reasons).