Principal English Translation: 

to make or do that thing; an applicative

Orthographic Variants: 
Frances Karttunen: 

-HUIĀ transitive verb-forming suffix This suffix is added to nouns to create verbs with an essentially applicative sense – to wield, use, or apply the thing named by the noun in relation to someone or something or to bring forth, produce the thing for someone Such verbs are generally paired with intransitive verbs in –OĀ, so that the –HUIĀ verbs may be considered the applicative forms of the corresponding –OĀ verbs.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 88.

Lockhart’s Nahuatl as Written: 

applicative of verbs in -oa. attached to a noun stem, gives a verb meaning to apply the thing denoted by the noun to something. James Lockhart, Nahuatl as Written: Lessons in Older Written Nahuatl, with Copious Examples and Texts (Stanford: Stanford University Press and UCLA Latin American Studies, 2001), 218.

Attestations from sources in English: 

A transitive verb that ends in -oa, when having the applicative ending (-huia, -lhuia, or -alhuia) becomes an honorific.
Michel Launey, An Introduction to Classical Nahuatl, translated and adapted by Christopher MacKay (Cambridge: Cambridge University Press, 2011), 215.

An ending that, when added to a noun, makes it into a verb:
pochtli = smoke (noun)
pochuia = to smoke
Robert Haskett and Stephanie Wood's notes from Nahuatl sessions with James Lockhart and subsequent research.