Using Atom editor is great visually the only issue is out the box .tpl is not recognized or is recognized as Smarty tpl. Thankfully the solution to this is simple.
Since the template engine on Nova is based on Blade install language-blade package. Once installed Atom needs to associate tpl with blade. To do this go to your settings and click Open Config Folder next click on config.cson look for Core: and add:
customFileTypes: "text.html.php.blade": [ "tpl" ]
Restart Atom. Now every .tpl file will have syntax highlighting.