The irony is that Nike somewhat recently started vanity sizing their shit (USA).  My last marathon the giveaway t-shirts were Nike brand, and I had to trade mine in for a size smaller because the Large was like a damn tent on me.  Even Medium was a bit looser than I like.    I can't even imagine what a current Nike XL++ is like.  I'm sorry, but if they can't fit in that size, get something cheaper than Nike because it should be too big on them in about 5 hot minutes of exercise and eating right.  But who am I kidding...