Ram Bahadur Bomjan, known as "Buddha Boy" by his devotees, became famous as a teenager after followers said he could meditate motionless for months without water, food or sleep.
"The district court on Monday found Bomjan guilty of child sex abuse," said Sikandar Kaapar, information officer at the court in Nepal's southern town of Sarlahi.
He is expected to be sentenced next month.
The 33-year-old guru has a devout following but has long been accused of physically and sexually assaulting his followers, and has been hiding from authorities for several years.
Nepal's Central Investigation Bureau arrested him in January at a house on the outskirts of the capital Kathmandu.
Police said he was caught with bundles of cash amounting to 30 million Nepali rupees (US$225,000) and another US$22,500 in foreign currency.
Dozens of assault complaints were filed against Bomjan in 2010. He said he beat the victims because they disturbed his meditation.
An 18-year-old nun also accused Bomjan of raping her at a monastery in 2018.
Police opened another investigation against him the following year after family members reported the disappearance of four of his devotees from one of his ashrams.
Before he went on the run, Bomjan still commanded a legion of followers.
At one point, tens of thousands of people gathered to witness his reputed miracles of meditation deep in the jungle.
Aged 16, Bomjan disappeared for nine months to wander the wilderness of eastern Nepal, prompting a round-the-clock vigil by Buddhist monks who prayed for his safe return.