Shaheda Akhter Ripa and Captain Shamsunnahar scored one goal each for Bangladesh while Amisha Karki netted one for Nepal.
In the day’s match, forward Shaheda Akhter Ripa opened account for Bangladesh in the 12th minute with a low-range right-footer inside the box (1-0).
In the 26th minute, captain and midfielder Shamsunnahar seal the fate of the game converting a penalty correctly for Bangladeshi girls (2-0).
After the half-time, Nepalese forward Amisha Karki scored for her side with long-range left-footed shot outside the box (2-1) but Bangladesh successfully maintained the lead until the final whistle.
The game saw getting two yellow cards – goalkeeper Sabitri Kisan of Nepal and defender Surma Jannat of Bangladesh.
Bangladesh will face holders India in their remaining match on October 13 at the same venue.
The top two teams of the four-team fray will play in the final on October 15.
Earlier, Bangladesh made a flying start beating hosts Bhutan by 2-0 goals in their first match last Wednesday.
Bangladesh clinched SAFF U−15 Women's Championship title in 2017 beating India by 1-0 goal in the final at Kamalapur Stadium here on December 24.
Bangladesh: Rupna Chakma, Nasrin Akhter, Unnoti Khan, Afedia Khandokar, Surma Jannat, Shamsunnahar, Rehena Akhter (Nusrat Jahan Bristi-82nd), Shohagi Kisku, Rozina Akhter (Swapna Rani-57th) , Shaheda Akhter Ripa, Nowson Jahan (Mahfuza Khatun-64th).
Nepal: Pratiksha Chaudhary, Man Maya Damai, Preeti Rai, Amisha Karki, Anu Rai, Sushma GT (Sunkala Rai-82nd), Nikita Thokar, Sabina Chaudhary (Manju Kumari Khadka-37th), Puspa Gurung, Sabitri Kisan, Mandira Rai (Mamata Pun-29th).
Referee: Kanika Burman (India).