Nero or any burning software automatically add the track numbers. The info or meta data is added with software made for this, the Track number-artist-genre- and then track title are all separate parts of the meta data for each song. We just name the song when exporting, that's all.
If you really want track numbers as part of the title just type it in when naming the export.
Or right clicking the file and "rename" it in windows.
But then when you burn the CD there will be two track numbers, and if you change your mind about song order??