I don't know about the one that the embassy issues. It is always good to make one from local authority (VDC or Municipality). In the USA, birth certificate is supposed to have both of your parent's name on it. Sometime, USCIS official will not pay much attention and let you go even if your mother's name is missing in birth certificate. I know people who have been issued green card without mother's name in birth certificate. You can try without it but you never know. So, it is always good to make one with both of your parent's name. If you can get one from your Nagarpalika in English, it should be enough. You don't need foreign ministry stamp.