to weld or solder something with tin (see Molina)
amochiotia. nitla. (pret. onitlaamochioti.) estañar algo. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 5r. col. 2. Thanks to Joe Campbell for providing the transcription.