Nally’s major work, The Irish of Erris, Co. Mayo: a phonemic study was published in 1968. He was a contributor to Éigse, Celtica, and Dinnseanchas and also published an article on the Hiberno-English dialect of his native townland of Emper, Ballynacargy, Co. Westmeath in The Journal of the International Phonetic Association.

He donated a portion of his papers to the Academy in 1982 and the remainder was bequeathed to the library in 1993. The collection is made up of handwritten notebooks, drafts and transcripts from articles, a small amount of correspondence and primary material collected by Nally in the course of his research (e.g. song words, information on placenames, cards and lists of Irish and Hiberno-English words).