I currently have on my CV a list of conferences I organized, or co-organized, a list of invited talks, a full list of talks, etc. Recently I have been asked to chair a session in a prestigious conference. I am very honored, and thus wondered: is this something I can feature on my CV? If so, would somewhere along with the conferences organized be "standard"?
I see absolutely no reason why not. It fits perfectly well into "other academic achievements, honors, and activities" (or whatever else your title of this part is). Just don't declare it the biggest achievement in your lifetime and provide the relevant details (conference name, level, session, etc.) in a reasonably full and concise format so that people can appreciate what you are talking about.
The short answer is yes. Anything that can be considered meriting can (or should) be added to a CV in my opinion. I have a heading "Other meriting academic miissions" in my CV where I list things that I consider meriting but do not fit under other headings where the list is longer. this includes, invited talks, tenure evaluations, etc.
My strategy with my CV is to add everything into a "master CV" and then remove parts depending on the purpose of the CV. Therefore, add the meriting tasks you are asked to do. It is easy to remove them if they are irrelevant for the specific purpose.
Chairing a session during a prestigious conference is certainly a good indication that you are recognised within your community (at least to the conference committee) and they value your contributions to the field. It should be definitely part of your CV (and online CV if you do have one).
These conference chairmanships speak well of your "administrative" ability. Some universities prize this, whether or not they say so. So list at least this one, and possibly others, on your CV.
This don't help your "scholarship" credentials per se. But even scholarship is about networking, and many professors will therefore value you for the contacts you have and the doors that you can open for them.