He worked alongside Vimalamitra translating the mahyoga and atiyoga tantras, including The Guhyagarbha Tantra, the root of the eighteen great tantras. As Jamgon Kongtrol relates in volume 2 of the Treasury of Knowledge, where Nyak Jnanakumara is brought up repeatedly,

Lalitavajra, Shri Singhaprabha, and Buddhaguyha explained this tantra

Vimalamitra, Ma Rinchen Chok, and Nyak Jnana Kumara translated and taught it

Rongzom Chokki Zangpo, Longchenpa, Chomden Rikpe Raldri, and others spread it.

Zurpa's especially exalted doctrinal tradition dwindled to become a slender hair

The brothers of Mindrolling Monastery revived the doctrine's dying embers

Jamgon Kongtrul continues a bit later:

"Moreover, as the saying relates, 'The vajra way's doctrine was first transmitted to Nyak, then to Nup, and finally to Zur.' Four doctrinal transmissions' streams from the great masters Padmasambhava, Vimalamitra, Berotsana, and Yudra Nyingpo collected in Nyak Jnana Kumara.

[The four streams are] the stream of scriptures of explanatory texts, accompanied by major commentaries and [summaries of ] the main points; the stream of profound instructions for meditation from the oral lineage, accompanied by texts on crucial points of instruction and direct guidance; the stream of empowerments' blessings, accompanied by techniques for their conferral and pointing out instructions; and the stream of the practical instructions for accomplishing activities, accompanied by [rituals for] the doctrine's guardians and wrathful mantras. Nyak Jnana Kumara's principal disciples were eight whose name included Pal, among whom Sokpo Pelgyi Yeshe imparted every profound instruction to Nupchen Sangye Yeshe. "

Dilgo Khyentse Rinpoche had a strong association with Nyak Jñānakumara. In Brilliant Moon, the Autobiography of Dilgo Khyentse Rinpoche, Nyak's his cycle and teachings are brought up repeatedly, including how when Khyentse Rinpoche was at Karma Monastery "there was a statue of the four-armed protector Mahakala, which was the practice support of the Seventh Karmapa. It was kept in a sandalwood box and only shown to special people. I asked to see it and discovered a yellow scroll with dakini script in its arms, which I took and gave to Khyentse Chökyi Lodro. From this scroll I wrote down the Nyak Kilaya.

In Sacred Ground, Jamgon Kongtrul identifies Chokgyur Lingpa as a manifestation of Yeshe Zhonnu.

Furthermore, in The Ruby Rosary Kyabje Thinley Norbu Rinpoche offers a commentary on a short prayer written by his father H.H. Dudjom Rinpoche illuminating the lives of great yogis, scholars, and masters of the Buddhist lineage in addition to describing the early spread of Buddhism in Tibet beginning with the direct disciples of Guru Rinpoche such as Nyak Jñānakumara.

TBRC Reference: http://tbrc.org/#!rid=P6525

Treasury of Lives Site: http://treasuryoflives.org/biographies/view/Nyak-Jnyanakumara/9121