You can't - the only sorts of feeds enabled by default on chat is RSS. We use it to feed external news sources and SE posts into chat as needed.
Chat itself has no RSS feed mechanism (and if you're going to go so far as to write a bot to scrape chat to convert it to RSS, might as well go the whole hog and build a bridge).
So simple answer is there's no way ...
For the latest 30 posts:
To get a feed of your specific scenario:
It seems simply appending /feeds to the site you desire will return the last 30 posts. Additionally, this link can be found at the bottom of the Hot Network Questions list on the home page for the site:
For a Single Post:
You can get a feed ...
Stack Exchange's Filtered Questions might be the workaround (or the solution) to this.
Example: All questions (including meta) on SoftEng.SE
The filter lists up to 100 non-closed questions, either all of them or based on certain tags, even from multiple sites. It also allows for emailing new questions directly, though only the filter creator can fill it.