Nyak Tso is a lake in Tibet, China about 30 km from Rudog — a town close to India's Ladakh.
Map of Bangong Co
It is also separated by a small water channel called Aot (?) and a sand shelf from Pangong Tso, which is a 130 km long salt-water lake in Ladakh, at 4,249 m elevation.
References
Nyak Tso Wikipedia(Text) CC BY-SA