to urinate (see Molina, who gives the example in the first person singular)
Alonso de Molina:
atl nicnoquia. (pret. atl onicnoqui.) orinar. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 8v. col. 2. Thanks to Joe Campbell for providing the transcription.