Vijayan's office said all arrangements are being made to bring back the bodies of the dead at the earliest.
State Tourism Minister Kadakampally Surendran said that he is in touch with the Centre while the state-run association of non-resident Keralites, Norka, is coordinating with the Centre.
The ill-fated group contained 15 people, including children, while the eight who died, were staying in one room.
The news was first confirmed by Union Minister for State for External Affairs V. Muraleedharan.
Speaking to the media, Muraleedharan said the tourists comprising two families of Thiruvananthapuram were reported dead in Daman in Nepal's Makwanpur district.
"The families of Renjith and Praveen (both aged 39) have been reported dead. What has been informed is they died due to suffocation from carbon monoxide that might have emanated from the room heater, as it was very cold. Their bodies have now been brought to Kathmandu and will be taken to Thiruvananthapuram," the Union Minister said.
The dead include the three children of Praveen, his wife, Renjith, and one child, while his elder child, who was sleeping in another room, was saved.
Praveen, who hails from Thiruvananthapuram and is working in the UAE, had returned for a holiday.
"His wife is a nursing student and is at Kochi, and they live there along with their three children. They left for Delhi last Saturday, and along with their common friends from Delhi they went to Nepal," one of Praveen's relatives told the media.
Renjith, hails from Kozhikode and had earlier worked in the IT industry.
"He started his own business in Kozhikode and his wife works in a bank," said a neighbour of Renjith.
According to a Himalayan Times report Superintendent of Police Makawanpur District Police Office, Sushil Singh Rathaur, confirmed that the Indian nationals were pronounced dead on arrival at HAMS Hospital in Kathmandu.
The eight Indian nationals, two couples and four children, were part of a group of 15 people who had travelled to Pokhara from Kerala, and were returning home. Police said that on the way back they had stopped at the Everest Panorama Resort in Daman.
According to the resort manager, the guests, who had arrived at around 9:30 p.m. on Monday from Pokhara, were staying in a room and turned on a gas heater to keep themselvesw warm. Although the group had booked a total of four rooms, eight of them stayed in a single room, while the remaining slept in the other rooms, the manager said. He said all the windows and the room door were bolted.
Police were informed of the guests' unconscious state after other members of the group went to check on them this morning, the manager said.
Subsequently, a helicopter airlifted the eight tourists to hospital in Kathmandu where they were declared brought dead.
( With inputs from IANS )