Hmm do you mean you want to create multiple cells from a single prompt - some code cells, then some markdown cells, then some code cells and so on?
The sidebar can certainly produce code mixed with markdown but right now, we process the markdown and show visually.
The cell level Cmd + K shortcut only works on a given cell to create or edit code and fix errors. Just tested it and it generates markdown well (just start your prompt with "this is a markdown cell")
In the sidebar/chat window, it should be trivial to not parse the markdown and just show it raw. I'll work on it. In the main notebook, it's a bit harder but we are planning to allow multi-cell insertions but it will probably take 2-3 weeks.