A certain user was of particular help to me in one of my questions. I would like to talk with him some more on the same topic. Is there any way I can invite him into a chat room, or somehow communicate with him (if he is willing)?
Usually you should be able to create your own chat room (having at least 100 rep) and invite this user there - in easiest case when you both are already in an other chat.
I tried to figure it out to give you a more detailed explanation, but I failed to log in.
Here you have a similiar question, offering some answer and link to a next question.
(I don't know why, but when I click here at top on "chat", it shows me I need to log in. After clicking there, it provides me the usual ways to log in. So I got logged in on main SE site, but returning to chat declines that I am logged in. Maybe it has to do that I deny a referrer while browsing.)