With the FileBot GUI, you currently need to do it this way.
/nas/movies/{n} ({y}) [imdb: {imdbid}]/{n} ({y})
Notice the use of [ ]. It should still find the embedded ID.
FileBot allows us to use {tmdbid}, {imdbid} or just {id}
Depending on the syntax you use (I would check using the GUI tool first, {id} might be the easiest. {id} is either IMDBID or TMDBID - whichever it matches.
Let me or chrisallen know please if any difficulties?