to warn or caution someone about what is best for him or her (see Molina)
IPAspelling:
nemɑtʃiːtiɑ
Alonso de Molina:
nemachitia. nite. (pret. onitenemachiti.) aduertir o auisar a otro delo que le conuiene. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 66v. col. 2. Thanks to Joe Campbell for providing the transcription.