to store things, or to gain something from selling things (see Molina)
Alonso de Molina:
achi nicnextia. (pret. achi onicnexti.) grangear o ganar algo en lo que se vende. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 2r. col. 2. Thanks to Joe Campbell for providing the transcription.