I believe Coinbase used to do this, @john_mardlin could you confirm?
In short, you’ll want to Embed Comments With JavaScript, but I don’t know to what extent Zendesk’s article system supports that. We’ve heard from customers that it was hard to maintain.
Have you experienced a lot of responses in this or similar areas in the past? In our experience, comment areas like these are very rarely used, so keeping up with the two separate comment platforms might not be such a chore after all. That said, having it all in Discourse would of course be preferable!