If I understand correctly ...
This is not a "tag", but a so called "format string", it defines the format resp. structure of a string.
A tag (think of a laundry label) is something called like ID3v1, ID3V2.3, ID3v2.4, APE and so on.
A tag can be appended or prepended to the music data.
A music file can contain different types of tags (often this causes errors and more work).
Different player devices or computer systems may support different tag types.
A tag field is some storage place in a tag.
A tag field has a name, e. g. "TITLE" and a content value, e. g. "This is a title".
To address the content resp. to extract the content of a tag field, Mp3tag uses percent signs around the tag field name (like many other tagging applications too).
So the string "%TITLE%" means: this is a handle or variable name to let the user work with the content of the "TITLE" tag field.
In your case ...
... you have a music file of type MP3: "Track 1.mp3"
... the file contains actually a tag field TITLE: "Chance Big Country 01 The Crossing (7-83)"
You want the filename to be set to the same content as stored in the title tag field?
This is pretty easy:
Use an action "Format value".
Field: _FILENAME
Formatstring: %TITLE%
To have this action always at hand, so create an "action group", give it a name of your will, create and setup this single action within the newly created action group. Run this action group against your selected files and Mp3tag will do the programmed step automatically for you.
But ... you gave this example ... to be the new filename ...
Because the file extension ".mp3" is located within the new filename and there seem to be different track numbers, I assume that your proposal is erroneously misspelled, and should be written as:
Filename: "Big Country - The Crossing (7-83) - 03 - Chance.mp3"
If the tag fields within the music file in question got their correct values from a previous process, then you might be able to construct or assemble the filename directly from the tag fields:
Use an action "Format value".
Field: _FILENAME
Formatstring: %ARTIST% - %ALBUM% - $num(%TRACK%,2) - %TITLE%
Another easy way to solve the task of renaming the filename from tag field content is:
Use the Mp3tag converter "Tag - Filename" with ...
Formatstring: %ARTIST% - %ALBUM% - $num(%TRACK%,2) - %TITLE%
DD.20100330.1052.CEST