His lawyer said he would launch a higher court appeal.
Lamichhane has been the face of cricket in Nepal and the only player from the Himalayan country to take part in prominent Twenty20 leagues in India, Australia, Pakistan and West Indies.
The leg-spinner was suspended as Nepal's captain and taken into custody after police issued an arrest warrant for him over the assault in 2022, and was later released on bail.
Kathmandu district court official Chandra Prasad Panthi said Lamichhane should also pay about $3,770 as a fine and compensation to the victim.
Lamichhane was found guilty of rape last month and the sentence was announced on Wednesday. His lawyer said before the sentencing that Lamichhane would appeal against his conviction.
"We are not convinced about the decision of the court ... The court has whimsically declared Sandeep to be a convict. Sandeep will go to the higher court for justice," lawyer Saroj Ghimire told Reuters on Wednesday.
