I have issues with my nasal breathing; I had an operation, which didn't work.
I have been experimenting with nasal dilators for running and cycling and find them to be quite helpful.
https://www.amazon.co.uk/Airmax-Anti-Snoring-Nasal-Dilator/dp/B00STPNB90
Would it be safe to use them in sparring? They are very soft rubber. I doubt getting punched while wearing one would be any different from being punched without.
Would they be legal in kickboxing competitions?