This is an authentic Luchadore Mask used in the production one of the best films of all time. This mask was displayed in this frame on the wall of Ramses' house for the party scene.
I haven't been able to screen match it, so it may not have made it into the final cut, but there are several frames and BTS shots showing similar masks and how it was used on set. Authentic Masks from Nacho Libre are not easy to find, and this may be your only chance to own one! COA is from Premiere Props.