Comments list as Menu Item

I’ve tried searching this topic but have not been successful in finding what I think I’m asking for. That is, if it has a different term, I don’t know what the term would be. I’ve looked at about 50+ posts on the support forum but don’t believe any of them actually answered my query.

I’ve seen on some WordPress blogs an additional menu item that lists the lastest comments posted (post title, name of person, date). This would be very useful if new comments have been posted on old posts that are no longer showing in the first page or two. To keep the dialogue happening it would be really useful for visitors to see new comments have recently been added to an older post.

Is there a code I can put in the sidebar.php (I have several blogs using different themes) or a plugin that I can use to achieve what I’m looking for?