Principal English Translation: 

purposive action (went to do); or, full of, when preceded by a noun

Lockhart’s Nahuatl as Written: 

auxiliary form of onoc. ti- ligature plus onoc minus on-.
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), 239.

Attestations from sources in English: 

In Techialoyan manuscripts -toc seems to have a present progressive thrust, like -tica in most places.

nictequipanotoc = I am serving
James Lockhart, personal communication, May 23, 2008.

Coloyotoc, tzitzicazzotc. Iluiloya in aquin moteiluiaya ixpan tlatoani, ca tetlatzacuiltiani in tltoani, ioan tetlacocoliani = Full of scorpians, full of nettles. This was told to the person who made the accusations against others before the king..."for the king deals out punishment as well as favors." Thelma D. Sullivan, "Nahuatl Proverbs, Conundrums, and Metaphors, Collected by Sahagún," Estudios de Cultura Náhuatl 4 (1963), 144–145.