I think birthplace is the one mentioned on the Birth certificate! You need to go by birth certificate. If they are confuse, they might issue RFE! Can you write a letter to US embassy and get a letter stating it was misprinted or get a new passport! But please noteazied the document how u come to realize discrepency so late as birth- crrtificate has no use in Nepal,and Correct 1 is on the birth Certificate. USCIS can be such a pain to work with. So please verify and correct all discrepency before you file. You don't want to wait until you get RFE which will further delay the Processing times.
K tyo birth certificate english ma cha Patan ko? Natra can jhapa give you a birth certificate!! You have to fill birthplace pretty much in all forms such as I- 485, I-131, I-765 n so on! Also send originalm translated document together/ notrazied by lawyers if possible. Better be safe than sorry:)