Here's what I do...
I go to
www.who.is, and search a random domain twice. This is in non-incognito mode (i.e. regular browsing). Don't click anything, or do anything on the site, just type, and hit enter.
The reason for this is so that Chrome will pick up on the search pattern.
What I mean by this, is that since it knows where the search function is on the site, as a result of your using it, as it predicts you typing in "www.who.is", you can hit tab, and that will bring up a prompt in the address bar for "search who.is".
So my process goes like this...
Hit F6 to highlight the address bar
Type "who"
Chrome predicts "who.is"
I then hit tab
Chrome then prompts me as follows: "Search who.is: (query)"
I then type the URL, say, example.com
So it then appears as "Search who.is:example.com"
Then I hit enter, and it immediately pulls the record up for me.
This, in my opinion, is far superior to any plug-in, and takes me a matter of about three seconds to initiate a search on the whois.
Of course, this method can be applied to any whois service, I so happen to prefer who.is.