In order to be able to choose Google Drive as the resource provider you have to first install UnityGoogleDrive and Unity's Conditional Compilation Utility. Consult projects' readme for installation and usage instructions.
When the required third-party packages are installed and configured, set
Google Drive Root Path (folder in the root of your drive where you'll store the resource files) in the provider configuration and select the
Google Drive provider for target resource type in the configuration manager accessible via
Naninovel -> Configuration context menu.
You can share your Google Drive resources folder with other users to work in collaboration without the need to use version control systems or other complicated tools.