to be opposed to something, to disagree (see Molina); this verb seems to contain itoa ("to speak") and the directional hual (this way) (SW)
Orthographic Variants:
ualnitoa
Alonso de Molina:
ualnitoa. ni. (pret. oniualnito.) oponerse a algo. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 154v. col. 1. Thanks to Joe Campbell for providing the transcription.