Under the deal signed in 2013, Newmont had to spend A$500,000 to earn 70%.
The company has completed its expenditure obligations and opted to form a joint venture.
Officer Hill sits 34km southwest of Newmont's world-class Callie gold mine.
The project covers just over 206sq.km and is thought to host steeply plunging shoots, with the apparent fold closure to the east offering the potential to discover Callie-style mineralisation at depth.
Nova will retain a 30% stake and the two companies will form an operating committee to advance the project.
Nova managing director Avi Kimelman said Newmont would bring valuable technical expertise to the project.
"The decision by Newmont to proceed with the Joint venture agreement is a ringing endorsement of the quality of the Officer Hill gold project and its exploration upside in the Tanami region of Northern Territory, particularly with the projects close proximity to the 400,000oz per year Tanami gold mine and located within the circa 13 million ounce Tanami endowment," he said.
Nova is focused on Canada and last week announced plans to spin-out its lithium assets into a new company, Snow Lake Resources, which will see a Toronto listing.
Shares in Nova jumped by 7.4% to 2.9c, valuing the company at over $20 million. The stock peaked at 6.4c in January.