Found this post, I'm attempting to confirm if it works.
"If you are one of the early adapters of Apple's iPod Touches, you are probably pissed off to find out you can't get GTA Chinatown Wars on your 1st gen touch, because it's not compatible with it.
Well, I've found a solution.
1.) Download WinRar
2.) Go to your applications in iTunes and find the app that is not compatible with the 1st gen Touch, in this case GTA Chinatown Wars. Right click it and click "Show in Windows Explorer"
3.) Drag the .ipa file to your desktop.
4.) Right click the .ipa file and click "Open With..." Then find WinRar and open it with that.
5.) Double click "Payload."
6.) Click the .app file and on the top hit "Extract To" and extract it to your desktop.
7.) On your desktop you'll find a new folder "Payload." Open it and drag the .app file to iTunes. Make sure the other GTA Chinatown Wars file isn't on iTunes. The .app file on iTunes won't have an icon, but don't worry, there'll be an icon on your iPod touch.
8.) That's pretty much it! Enjoy."
Confirmed working. Most current OS on the touch.