If your USC sponsor and father/mother of the child meet the requirements they can lodge a Consular Report of Birth Abroad for a Citizen of the United State of America.
We did it this year for my daughter who was born in Australia. Her father is a USC.
Hello
My husband and I was in the same situation, we filed for the I130 on February and I got my NOA1 the 22 of February.
I got pregnant at the end of March. You have nothing to do more than wait your NOA1 and 2 got approved. It will not help the process to go faster the only things is now when you filed will be send to NVC you will have to prove that you can provide for 3 peoples ( i think its about 28/29k )
For your child you gonna have to go to Nigeria to declare your new born at the American Embassy. You will have to provide birth certificate and they will probably ask you and your wife questions too. After that, if everything goes well, your son or daughter will be granted of the US citizenship and will have a passeport.
I m 7 month pregnant still in the process of waiting the NOA2. When our daughter will be born, my husband will have to come back in France to declare her.
My husband is an American citizen so what i m telling you works if you are an American citizen. I don't know if its the same thing for Permanent resident.