Principal English Translation: 

mucus (see Molina)

Alonso de Molina: 

yacacuitlatl. mocos.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 30r. col. 1. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

YACACUITL(A)-TL snot / mocos (M) See YAC(A)-TL, CUITL(A)-TL.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 333.

Attestations from sources in English: 

From nose (yacatl) and excretion (cuitlatl). Snot.
Michel Launey, An Introduction to Classical Nahuatl, translated and adapted by Christopher MacKay (Cambridge: Cambridge University Press, 2011), 233.

ticacamacpil, tinenepiliztacapil tiez, ticamaҫapil, ticanponaton timuchioaz moiacacujtlapil ticpalotinemjz, tipinectontli tiez, tipineoatinemjz in tlalticpac, moiacacujtl chipintinemjz = thou wilt be stunted, thy tongue will be white, thy mouth will become swollen, puffed; thou wilt go tasting thy nasal mucus, thou wilt be pale, thou wilt go pale on earth, thy nasal mucus will go dripping (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), 117.