to be stupefied or deep in thought, not paying attention to what is said to one (see Molina who gives this example in the first person singular, ni-)
Alonso de Molina:
aye nicmattica. estar abouado o pensatiuo, no aduertiendo alo que le dizen. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 3v. col. 1. Thanks to Joe Campbell for providing the transcription.