Two goals for Vietnam were scored by Pham Hai Yen in the 53rd minute and Bich Thuy in the 64th minute.
Vietnam, who have targeted the second-place finish in Group D behind reigning champions Japan, faced significant obstacles from Nepal’s strong defensive formation in the first half.
Vietnam will play against Bangladesh on September 25.
The 19th Asian Games in Hangzhou, China, features a total of 40 sports and 481 events.
Vietnam dispatched a 504-strong delegation, including 320 athletes, to the tournament.
