Nacho Libre is loosely based on the story of Fray Tormenta ("Friar Storm"), aka Rev. Sergio Gutierrez Benitez, a real-life Mexican Catholic priest who had a 23-year career as a masked luchador. He competed in order to support the orphanage he directed.
Not as fun as I expected it to be. 'Nacho Libre' does do some things well, Jack Black is good and the wrestling scenes are mostly nicely done. However, I didn't really dig the rest of it - whether it be the laughter lacking humour, or the uninteresting story with the orphanage. It is at least a relatively short flick, but it isn't one I'd be in a rush to rewatch.