and if by chance, or perhaps (conjunction) (see Molina)
Alonso de Molina:
intlanazo. y si porventura, o acaso. l. mas. si. conjunction. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 39v. col. 1. Thanks to Joe Campbell for providing the transcription.