Principal English Translation:
nettle(s) (see Molina and Karttunen)
Alonso de Molina:
tzitzicaztli. hortiga.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 152v. col. 2. Thanks to Joe Campbell for providing the transcription.
Frances Karttunen:
TZĪTZICĀZ-TLI nettle / ortiga (M), chichicastle, mal hombre (planta) (Z).
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 315.
Attestations from sources in English:
Nettles (tzitzicaztli) are given as some of the essential items found in the "devil's houses."
Fray Bernardino de Sahagún, Primeros Memoriales, ed. Thelma D. Sullivan, et al. (Norman: University of Oklahoma Press, 1997), 116.
cujx aocmo çan, atl cecec: cujx aocmo çan tzitzicaztli = Perchance no longer is there castigation with icy water? Perchance no longer is there castigation with nettles? (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 6 -- Rhetoric and Moral Philosophy, No. 14, Part 7, eds. and transl. Arthur J. O. Anderson and Charles E. Dibble (Santa Fe and Salt Lake City: School of American Research and the University of Utah, 1961), 3.
Attestations from sources in Spanish:
in itzoaz, in imecauh, in icolouh, in itzitzicaz, in iteuh, in icuauh = la trampa, el mecate, el gancho, la hortiga, la piedra, el palo (El castigo) (centro de México, s. XVI)
Josefina García Quintana, "Exhortación de un padre a su hijo; texto recogido por Andrés de Olmos," Estudios de Cultura Náhuatl 11 (1974), 160–161.