You can add a field to MC with a name that
exactly matches the file tag name, both spelling and case, and MC will import the tag value into the new field.
So if the tag is actually ALBUM_SORT_NAME, then that is what the field needs to be named. Note that the Display Name of the field doesn't have to be the same, so you can give it a Display name of something more friendly, like "Album Sort Name".
Once the field has been created, if you have already imported the files, just select the files and run the right-click "Library Tools > Update Library (from tags)" function, and MC should be updated with the tag values from your files. Test with just a few files first. Make a Library Backup before that!
You can also use the Tag() function in a View to read the value of a tag directly from files. See
https://wiki.jriver.com/index.php/Accessing_and_Storing_Functions#Tag. This is useful for checking that MC can read the tag, and that you have the tag name exactly correct, but as it reads the file directly you shouldn't use it generally in Views. It would be too slow and resource intensive.
Also, if your ALBUM SORT NAME is just a rearrangement or combination of some other data in MC, then you could instead create a Calculated field, which would have an expression defined to calculate the value you want, and the field could be written to file tags if you wish. What do you put in your ALBUM SORT NAME?
Perhaps also share the file types you are working with (MP3, FLAC, ?) and the source of your ALBUM SORT NAME data (MusicBrainz, ?).
I thought I had read several discussions about this on the forum, but I can't find them quickly. Perhaps a more diligent search would find them. Maybe I am thinking of ARTIST SORT NAME.
https://wiki.jriver.com/index.php/Library_Fieldshttps://wiki.jriver.com/index.php/Tagginghttps://wiki.jriver.com/index.php/Tagging_Classical_Music