to crumble, chop up, tear up into little pieces, or grind something very well (see Molina)
Alonso de Molina:
cuechtilia. nitla. (pret. onitlacuechtili.) desmenuzar algo, omolerlo mucho. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 25v. col. 1. Thanks to Joe Campbell for providing the transcription.