Principal English Translation: 

makes a verb of a noun, i.e. to be or become that thing; having that quality

Lockhart’s Nahuatl as Written: 

derivational ending creating a verb meaning to be, become, or serve as the thing denoted by the noun stem to the left.
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), 235.

Attestations from sources in English: 

cualti (present) = to be or become good;
ocualtic (singular preterite);
ocualtique (plural preterite)