Unlimited if you can get past nepal security; once in the US it has to be declared and taxed if required.

Less than 10K doensnt need reporting in the form when you land.

I think I read somewhere, it's 5k. They even have limit on Nepali RS you can carry like 5 thousand of something. And on top of that , there is question for bank exchange, how much they will give u cash. I think not more then 500 case.

Basically, I forgot exact number but it's not much and probably safe to say, what ever bank will allow you to exchange and get cash based on US visa type you have.