you shall not do such a thing (literally, you will not see yourself doing such a thing) (see Molina)
Alonso de Molina:
maticchiuh. mira que no hagas tal cosa. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 53r. col. 1. Thanks to Joe Campbell for providing the transcription.