Principal English Translation: 

how? in what manner or condition?; how, what; by late period in New Spain, this worked in many ways like the Spanish "como", that (see Karttunen, Molina, Carochi/Lockhart)

Orthographic Variants: 
quename, quēnamih
Alonso de Molina: 

quenami? de que manera, o de que condicion es? o que arte o condicion tiene?
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 88v. col. 2. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

QUĒNAMIH pl: QUĒNAMIHQUEH how? in what manner or condition? / ¿de qué manera? o ¿de qué condición es? o ¿qué arte o condición tiene? (M) [(6)Cf.115V,(1)Bf.6r,(2)Zp.15,190]. B and Z end in -MEH rather than -MIH. Z has QUI for QUĒ. AMIH is separable to the point that MACH can be inserted to form QUĒMMACHAMIH. See QUĒN.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 209.

Horacio Carochi / English: 

quēnamî = how, in what or a certain manner
Horacio Carochi, S.J., Grammar of the Mexican language with an explanation of its adverbs (1645), translated and edited with commentary by James Lockhart, UCLA Latin American Studies Volume 89 (Stanford: Stanford University Press, UCLA Latin American Center Publications, 2001), 510.

Lockhart’s Nahuatl as Written: 

how, how constituted, interrogative. preceded by in, as, or dependent how. Can have an abs. pl. quēn amihqueh in which the second element bears the subject prefixes if any. quēn, a preterit agentive base amih. 231
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), 231.

Attestations from sources in English: 

quenami (adverb) = as, the same as
Daniel Garrison Brinton, Ancient Nahuatl Poetry: Containing the Nahuatl Text of XXVII Ancient Mexican Poems (1877), 160.

Thus a common equivalence in Stage 3 Nahuatl involved quenami, originally meaning something that is in a certain manner, most often used interrogatively (what is it like?), which became the equivalent of Spanish como in the specific sense of as, in a certain capacity. In the Puebla text we find that in an emergency the bishop attired himself quenami se soldado, como un soldado, as soldier (f. 18v)
Here in This Year: Seventeenth-Century Nahuatl Annals of the Tlaxcala-Puebla Valley, ed. and transl. Camilla Townsend, with an essay by James Lockhart (Stanford: Stanford University Press, 2010), 48.

nehual quenami jues = I as judge (functioning like "como," in the capacity of);
quenami mitlania se pedaso tlali = how–or that–a piece of land is requested
James Lockhart, "Language Transition in Eighteenth-Century Mexico: The Change from Nahuatl to Spanish Recordkeeping in the Valley of Toluca," in Nahuas and Spaniards: Postconquest Central Mexican History and Philology, Nahuatl Studies Series, No. 3, James Lockhart (Stanford: Stanford University, 1991), 107.

quenamj molli = all kinds of sauce (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 2 -- The Ceremonies, no. 14, Part III, 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), 78.

in quenami yntequihu iezqui = how their duties are to be (Tlaxcala, 1547)
Beyond the Codices, eds. Arthur J.O. Anderson, Frances Berdan, and James Lockhart (Los Angeles: UCLA Latin American Center, 1976), Doc. 22, 120–121.

Canpa oquitocac ymetoton San quenami Sentecpantli = where he planted his small magueyes, about twenty of them
The meaning here might be "como viente," i.e., about twenty, or possibly it could be as they are in a row. (San Miguel Aticpac, Toluca Valley, 1711)
Caterina Pizzigoni, ed., Testaments of Toluca (Stanford: Stanford University Press and UCLA Latin American Center Publications, 2007), 73.

Attestations from sources in Spanish: 

ca mitlaniliz yn amatlynic mochi motamachihuaz yca in tlalcuahuitl yn quename yc mani = que se le pidan los papeles y se mida con vara de medir tierras cómo está
Vidas y bienes olvidados: Testamentos en náhuatl y castellano del siglo XVII, vol. 3, Teresa Rojas Rabiela, et al, eds. (México: CIESAS, 2002), 232–233.