If I remember correctly, an American Notary does not certifies as to the veracity of what it is written in the document to be notarized, but only as to the identity of the one signing the document.  So, you can write one stating that you are King Solomon, 500 years of age, and as long as you sign it in front of the notary, and can prove your name is King Solomon, he will affix the seal to it.

So, your chances of locating an American Notary in Chongqing, or in all of China, are just about nill, unless you take the document to the US Embassy in Beijing or one of the four Consulates.  Try to0 locate a Chinese notary in your city, and see if he will notarize the document after witnessing your signature and showing him proper ID.

This worked for me with some SS forms I had to fill out and send back, I used a Chinese notary and no one said anything about it.

The only way to get an American Notary is by going to Chengdu to the American Consulate.  I had to have some things notarized to sell property in the USA.  This is the only place, legally, to get it done.  Beware of scams in CQ. 

But, be aware, a lot of things CAN be notarized by Chinese authorities.  Go to any Notary office in CQ and ask.  Take a friend who is fluent in English and Chinese.