to protect myself from the sun and rain with a kind of shield (see Molina; this example is given in the first person singular)
Alonso de Molina:
chimaltitlan nicalaqui (pret. chimaltitlan onicalac.) lo mesmo es que chimalcaltia. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 21r. col. 1. Thanks to Joe Campbell for providing the transcription.