The free open source Atom text editor from Github is one of several development tools that have gotten a lot of traction in recent years amongst web technology developers looking for an alternative to the big IDE's like Visual Studio, Eclipse or the JetBrains editors.
Atom is aimed at the same niche often filled by Sublime Text, Vim and Notepad++, namely to provide a small self contained code editor able to work on multiple files at a time, and with available plugins that provide programming features like color syntax highlighting, smart indentation and robust search and replace.
One of the design goals of Atom was that it be extensible, and as developers have begun to use it, a large number of "Packages" have been contributed. One of these packages "atom live server" provides an integrated HTTP server with "live reload capability."
To use it, you open your primary html page file in Atom, and start the atom-live-server using the Packages menu or one of a number of different key bindings that launch the HTTP server on a particular port. What's really convenient, is that by default, it will open a browser and load the page for you, connecting to whatever port the live server is listening on.
Atom Live Server will use your default system browser, but in many cases that might not be the browser you want to work with. The Live server supports a project by project configuration option. You need to create a .json file in your project directory named .atom-live-server.json In this file you simply need to include a json block with a "browser" key. While this is documented on the Atom Live Server page, there isn't specific instructions on how you set Atom Live Server to open Chrome. In fact, there are a number of different options you can put in the atom-live-server.json file, few of which are documented. They do point you to the live-server github page, which is a node app that provided the basis for atom-live-server. The Params documented on startup give you a lot of different options for things like supporting https, however there is nothing there to help you know what "browser" string to use to get chrome to open.