Following attempts to install Windows, this is as far as I've got (not very far - I wouldn't recommend trying)...

1. Download TortoiseSVN and clone the latest Chombo to /Users/myusername/chombo
2. Install chocolatey [https://chocolatey.org/install]. I did the powershell version, after first launching an administrative powershell - installation is achieved through one line of code, as provided on their website.
3. Install make through chocolatey: choco install make... but it didn't let me compile Chombo...