This will show you how to use spotlight to search google and display the results in chrome, firefox or any other browser

1) open safari
2) go to preferences > general
3) make sure ‘google’ is your preferred search engine.
4) make sure the browser you want to use to perform the search is the default web browser.

now, launch spotlight search and type something in, when you click on ‘search the web’ it will open your default browser and will show the google results for that search .