I've discovered how to do it for both administrative and non-administrative users. In the Chocolatey non-administrative section of the docs, it says that to install Chocolatey as non-admin, first we have to define a ChocolateyInstall environment variable pointing to a location where Chocolatey should be installed and all users have access (I've used C:\Users\Public\Chocolatey folder). That variable can be set at machine or user level. If we define it at machine level, the same Chocolatey installation can be used for both admin and non-admin packages installs. After setting the variable, we should procede to Chocolatey install, which can be done either as admin or non-admin user.