The question references “IFS” and “NFS” together as if they are the same thing. Then it mentions “UNIX NFS migration” as if a Unix system might be involved. It seems as if a NFS share is mounted in the IFS and copies are done from there to /QNTC by an AS/400 program or user. Or maybe there simply is some confusion that is bringing “NFS” into the question because there’s a thought that the AS/400 is a Unix system.
Some clarification of why “NFS” is mentioned at all would be helpful.
However, the base question of ownership is simple. When an object moves to a different system, the owner will necessarily change. The two systems have entirely different users even if their names are spelled the same. When an object is moved to a Windows system “ownership” is an entirely different concept, not even really relevant. What is relevant will be “permissions”.
Assign permissions when the object is placed on the Windows system. Use Windows functions to do that. Use Windows commands to set permissions (or the ‘access control list’).
See for example: How To Automate Folder Permissions, Windows change access permissions from the command line and How To Change File Permissions Command Line for examples.