You can do that in Firefox and with more granular control. If you right click in a search box you can choose to "Add a keyword for this search" and then you can make the keyword whatever you choose.
For example: I have a folder in my bookmarks containing like Youtube which is this url https://www.youtube.com/results?search_query=%s&oq=&gs_l= associated with the keyword "yt" so I can type yt <search term> and it loads the Youtube results. I've also added one for the Mozilla Developer Network (mdn <search term>), Python Documentation (py2 <term> or py3 <term>) and I add others as I use them more.
I use that, but it isn't as good as it used to be in Opera. Opera auto-completed your search using the target search engine's autocompletion. I don't use Chrome often enough to know if it does that too, but it might make me switch. (I switched from Opera to Firefox because of the plugin ecosystem.)
Chrome has all those features too, it let's you add search engines via right-clicking a searchbox, ,you can change the search keyword, and "<search-keyword> <search-terms>" in the omnibar works as described by you.
For example: I have a folder in my bookmarks containing like Youtube which is this url https://www.youtube.com/results?search_query=%s&oq=&gs_l= associated with the keyword "yt" so I can type yt <search term> and it loads the Youtube results. I've also added one for the Mozilla Developer Network (mdn <search term>), Python Documentation (py2 <term> or py3 <term>) and I add others as I use them more.