How to Add Nested Comments to WordPress
Was following up with questions on my blog and it really bugged me that my replies to comments didn’t appear as replies to user comments. They just appeared as a totally new comment down the line.
I enabled nested comments under Settings > Discussion, but it didn’t change anything. I noticed there was nothing in the code to differentiate between first and second level comments.
Finally, with a little more research I was able to find a helpful article on this, which mentioned using the WordPress Thread Comment plugin. I installed the plugin, and it works exactly the way I want it, even on existing comments.
In your WordPress admin area, go to Plugins > Add New and search for WordPress Thread Comment. Install and activate the plugin and make sure that nested comments are enabled under Discussion, and you’re ready to go!