It's possible using something like
OpenMPT, but the two formats are so different in capabilities that I can guarantee you that converting IT to MOD will give you unlistenable results unless the IT module is simple you are willing to put a lot of work into a manual conversion. MOD to IT, on the other hand, doesn't cause many problems.
Note that if these games are somewhat recent (from the last decade or so), chances are high that they use BASS or a similar library which can handle several formats, including MOD and IT, so a conversion might not be necessary.
