They reached the 8,850m (29,035ft) summit on Wednesday evening.
The Sherpas were hired by expeditions to carry equipment and secure ropes on Everest for about 300 foreign climbers trying to make the ascent.
May is the best month for climbing and more expeditions are expected to reach the top in the next few days.
Climbs from the Nepali side over the last two years have been hit by natural disasters.
An avalanche triggered by a powerful earthquake killed at least 18 climbers in 2015, and 16 Sherpas were also killed by an avalanche in 2014.
The two disasters meant that hardly any climbers were able to scale the peak. Last year's climbing season was cancelled, and nearly all climbers in 2014 similarly were forced to abandon their attempts.
However, one Chinese woman made an ascent in early May 2014, weeks after the deadly avalanche.
Nepal Mountaineering Association President Ang Tshering Sherpa told the BBC's Surendra Phuyal in Kathmandu that Wednesday's climb was no simple feat.
"Although they were planning to reach [the summit] much earlier in the day, difficult climbing conditions near the Hillary Step - a major climbing hurdle around 70 metres below the peak - delayed the Sherpas' plans," he said.
"Because of heavy snow and ice, it took more than four hours for them to cross the Hillary Step."
He said the Sherpas had succeeded in laying down climbing ropes along the trail to the summit for other climbers to use.
The Sherpas were now descending the South Col part of the mountain, he added.
This year, Nepali authorities are encouraging climbers to return to Everest and other peaks by honouring permits issued in the past two years.
Overall, more than 700 foreign climbers belonging to nearly 100 teams are vying to scale several Himalayan peaks from the Nepali side, the Department of Tourism says.
The authorities this year have for the first time allowed helicopters to transport ropes and other climbing gear up part of the mountain so that Sherpas can avoid carrying equipment through the dangerous Khumbu Icefall, which has become much more dangerous after last year's earthquake.
May is also one of the best months for climbing Everest from the Tibet side, with about 550 visits a day to the base camp there at the height of 2015, according to the Xinhua news agency.
Nine Sherpa guides have taken advantage of good weather to scale Mount Everest for the first time in two years from the Nepali side, officials say.