If there was chile on it, it wasn't poutine. Poutine, better known as Ambrosia, or food of the gods, is quite simply fries, cheese curds, and gravy, typically a type of turkey gravy for best results, though I haven't been in a place where you get the true poutine gourmets in many a year.
As for mayonaise on chips... that sounds utterly disgusting, and I have never actually seen anyone do so. So, I'm kinda thinking that's a myth.