Depends on how you put it on. I do Chromium, which is pretty much the same. I download the win32-zip archive to avoid install. It's a good idea to keep a couple of backups of your chrome settings folder. Sometimes when you update to a newer version where they changed something in the settings it won't let you go back. That's why it's a good idea because you can just copy the old settings folder back to go retro.
For the exe file and subfolders I make a folder that's not under Program Files. Likewise I back that up. If the different version doesn't work well I just copy settings folder and exe folder back and all is well again.
Chromium has its settings folder in
C:\Users\Owner\AppData\Local\Chromium folder if the user name is "Owner"
Chrome should be similar.
Just unpack the zip archive in a separate folder. In fact just today I went from Chromium 11.x back to version 10.0.602.0.
When you copy the zip file to your Chrome or Chromium folder that has the zip file, make sure you don't delete the Dictionaries and extensions subfolders. All the rest can go as they are replaced with files frome the zip archive. If you delete the "extensions" subfolder you could end up having to reinstall all your extensions. When you run the portable copy you just put on, take a look at the Settings Under The Hood tab in Options. If you don't want chrome tracking all your visited sites turn off the settings about "suggesting" a site if the url you type in doesn't get a hit. All that stuff is forwarded to Google, even in Chromium.
If you installed chrome I would try setting up the portable archive and see if it picks up your settings from the other copy. Then once you have it how you want, uninstall the original chrome. Be sure to keep backups of your chrome folders in case it removes more than you want it to.
If you get hit with the "cannot be used as it is from a newer version of chrome" then you might have to bite the bullet and configure everything again after removing all the stuff. You should only have to get hit with that once until you are set up to use only portable configs and have your folders backed up. Usually if you go back a version or two it will stop giving the warning about the version being from a newer chrome. It's not like you have to save a copy for each version. Just now and then.