By default files which are in UNA storage are already send proper headers to be cached by browser, default setting is 30 days, you can change it in sys_objects_storage table cache_control field, however it's for public files only. Private files are cached for short period of time, the same as token_life, by default 6 minutes.
Also I believe that more correct setting for Nginx to cache static files would be (if UNA is installed in the domain ROOT folder):
there is the difference where Cache-Control: max-age=0 does not exist in the request header.
It seems like the images like above in timeline, they are not cached also here at una, what shall we do to make them cached? Because our current timeline version is causing a lot of image files to reload each time which takes a lot of time and network cost.