Nokia Mobile has rolled out the October Android Security update for their last year's Nokia 3. Just like most Android Security patches, this update is pretty small at 89MB in size and just brings the Google's latest October Security update.
The update has been rolled out in India and it should be available in other markets too. You can manually check for the update by going to Settings > System > System updates. You can learn more about the October security patch on Android Security Bulletin.