This behavior is supported, but I guess it was never documented. The default queue we pick is Ranked Solo 5x5.
The complete list of options for queue is:
ranked_solo_5x5
ranked_tft
ranked_flex_sr
ranked_flex_tt
As Emily posted above, the format is:
$(leagueoflegends summoner_name region queue_type)
If you’re still having issues, please post the exact syntax you’re using, the message you’re sending when testing, and the response Nightbot provides.