yacamitl.

Headword: 
yacamitl.
Principal English Translation: 

very thin nose plug (literally, nose arrow) (Olko); or, a nose rod (Sahagún)
Justyna Olko, Turquoise Diadems and Staffs of Office: Elite Costume and Insignia of Power in Aztec and Early Colonial Mexico (Warsaw: Polish Society for Latin American Studies and Centre for Studies on the Classical Tradition, University of Warsaw, 2005), 167–168.

Attestations from sources in English: 

chalchiuhiacamjtl, teuxiuhiacamjtl = A green stone nose rod; A fine turquoise nose rod. (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 8 -- Kings and Lords, no. 14, Part IX, 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, 1951), 28.

yacaxihuitl = nose turquoise;
yacapitzalli = thin nose thing
Justyna Olko, Turquoise Diadems and Staffs of Office: Elite Costume and Insignia of Power in Aztec and Early Colonial Mexico (Warsaw: Polish Society for Latin American Studies and Centre for Studies on the Classical Tradition, University of Warsaw, 2005), 168, 170.

Attestations from sources in Spanish: 

xiuhyacamitl = "y luego le aguxeran la ternilla de la nariz y le pusieron un pequeño y delicado pedaço de esmeralda muy delgada" (Tezozomoc 2001, 248)
Justyna Olko, Turquoise Diadems and Staffs of Office: Elite Costume and Insignia of Power in Aztec and Early Colonial Mexico (Warsaw: Polish Society for Latin American Studies and Centre for Studies on the Classical Tradition, University of Warsaw, 2005), 168.