your question did not say when did you send the application. so if i suppose you send the application for i130 on july 1 they received your case. it should be i797- Notice of action.

The letter you received is to say hey we have your case on queue.

it will take time to get approved. At least 9 months wait, don't get scared it depends upon the service centre that is looking your file. I don't see National Benefit Centre's as you stated (MSCXXXX it is a National Benefit Centre known as MSC), time now but it used to be there before which is supposed to initiate your application process once your I130 is approved they will send you a letter stating you are not eligible at this time to Adjust status as there is a visa number which should be available to specific category if you are applying based of your Greencard spouse or what ever your relation is NOT A CITIZEN (CITIZEN has different route). once your visa is available NBC will send you a letter to start your application then you are about to apply for adjustment which i think about 2 years or sooner at least for NEPAL.

This is not a legal advice but i am in the same boat since July 2016 and it is out of experience. if you want to understand more process feel free to PM me.