It depends on if they go strictly by the Apex Tournament Ruleset (which most do) I would just ask the people running your tournament. It does look like pro controllers are allowed though!
Apex Ruleset on Controllers:
Controllers: Alternate or custom controllers/adapters are allowed.*** Players
suspected of using turbo functions or other macros are subject to immediate
disqualification from the tournament. Players are responsible for setting up
custom controllers in a timely manner.
Players who use the Wii Remote must take the batteries out of the Wii Remote
when not playing. If the Wii Remote is still synced up to a Wii with the batteries in,
you could unintentionally disrupt a match. If problems persist, a DQ may happen.
Any malfunctions or errors associated with your controller are your responsibility,
so make sure you’re using the correct settings BEFORE a match is played. Both
parties need to agree if a match is to be paused or restarted because of a
controller problem
Alternate Controllers: The Wii U Gamepad, Nintendo 3DS, and
Nintendo 2DS are banned from use as controllers. All other controllers are
acceptable for this event.