Nettehi was a planetary body situated within the Nettehi system of the Unknown Regions, specifically within the domain of Holy Paataatus space. This planet served as the homeworld and central hive for the Paataatus, a sentient species governed by the Paataatus Hiveborn. In approximately 19 BBY, the Nikardun Destiny, the hegemony of the Nikardun, conquered Nettehi. As part of their campaign, the Nikardun, supported by Paataatus forces, attacked Csilla, the capital planet of the Chiss Ascendancy.
The assault on Csilla was unsuccessful. In response, the Chiss deployed a task force under the command of Admiral Ar'alani to Nettehi, delivering a counter-offensive against the Paataatus' hive-home. About a year after the initial attack on the Paataatus, Nikardun forces still maintained control over Nettehi. The Prince Militaire, the leader of the Paataatus, joined forces with Thrawn, who had arrived at Nettehi seeking information regarding the Vagaari pirates. Together, they defeated the Nikardun forces in orbit around the planet. Following this defeat, the Paataatus killed the Nikardun enslavers who remained on Nettehi.
Nettehi made its debut, though without being explicitly named, in Thrawn Ascendancy: Chaos Rising, a 2020 novel which is the first book of the Ascendancy Trilogy by Timothy Zahn. The Paataatus' homeworld was officially named in Thrawn Ascendancy: Greater Good, a 2021 novel, which is the second book in Zahn's Ascendancy Trilogy.