Modding Chinese Imperial Government into AGOT?

It's probably possible. I would think you'd need to change the potential for it to fit along with the AGOT mod and then also change any relevant laws. I'm not familiar with any special decisions and/or events associated with it from vanilla (I don't play on that side of the map usually), but you might need to incorporate those as well.

I don't. That's part of why I said I'm not familiar with the government type. I haven't played a vanilla CK2 game with that government type so I'm not familiar with its mechanics or any special decisions or events unique to it. The government itself is in the feudal_governments.txt file in the governments folder. I said to check the laws files since modding governments and those files pretty much go hand-in-hand. I would suggest selecting all of the files and open them all up in Notepad++. Then search for instances of chinese_imperial_government using the search for all in all open documents. This will give you results at the bottom where it will display where those are located. Click on one and it will take you directly to the file and location of where that instance is. Once you know what and where the coding for the government is, you could carry that over to the AGOT equivalent files. After doing all that you could check to see if there are any special decisions, events, scripted triggers, scripted effects, etc. by following the same procedure.