Yes, you can add media from Google Drive into an editing project.
Use the direct file importing feature in Clipchamp that appears when you click on the down arrow importing media button.
A second pop-up window will appear. Choose an account to continue to Clipchamp. Click the correct email address linked to your GDrive files.
Once you have linked your Google Drive, another pop-up window will appear. Select the media file you would like to add to Clipchamp, then click on the select button.
Download the files from Google Drive to your computer and then add them to your project from there.
If you're on a Chromebook, you can add files to your Clipchamp project from your Google Drive as well. See Using Clipchamp on a Chromebook.