Yes, this is possible. AD for SMB access and Windows user identities is a different service from LDAP for UNIX identities. ONTAP can be a client for both. You'd just want to ensure the UNIX usernames match the Windows usernames for easiest configuration (ie, no need for name mapping rules).
See TR-4835 for info on configuring LDAP.
https://www.netapp.com/us/media/tr-4835.pdf
See TR-4887 for multiprotocol NAS info:
https://www.netapp.com/pdf.html?item=/media/27436-tr-4887.pdf
