The options for unstacked nfo files are anly available for posters and fanart and only then because various versions of XBMC were broken only allowing one or the other instead of both. All versions of XBMC have no issue grabbing info from an unstacked .nfo file.
In addition to this, MC uses the filename of the .nfo file to know the filename of the Media file.
eg if the nfo is named:-
then the media filename is
moviefile cd1.ext, and can easily be found with a quick search
This allows media to be played, and mediainfo to be used.
I will be adding support for movie.nfo, fanart.jpg and move.tbn soon for those who use folders for each movie, and in the longterm I will be changing the way the program starts so that filenames are not so important.
For the time being just use the unstacked names. They work on all versions without issue.