stucco (a noun; see Molina); Olmos (1547, f. 200v) translates tlaquilli as "encalar" (to stucco, a verb)
IPAspelling:
tɬɑkilli
Alonso de Molina:
tlaquilli. encalado, y bruñido. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 134r. col. 2. Thanks to Joe Campbell for providing the transcription.