can i integrate user manager with windows radius (NPS) ? so that i can control user download and uplodad usage and other properties.

I've not tried this, however: Rather than try to use usermanger, I think what you want to do is set your NPS server as a direct RADIUS server for your Mikrotik then setup Mikrotik Vendor Specific Attributes in NPS to control bandwidth.

Mikrotik Attributes:
https://wiki.mikrotik.com/wiki/Manual:R ... dictionary

Some info on configuring NPS:
https://community.arubanetworks.com/t5/ ... true#M3309

Mikrotik Radius Client Config:
https://wiki.mikrotik.com/wiki/Manual:RADIUS_Client