App like HackerNews but with tags and search capability

I'd like to build an application with forum capabilities similar to hackernews(threads and simple UI) however, I'd like to add tagging at each level i.e'd also like to add search capability at each level based on username/tags. I am here to ask if there are any existing open source solutions that I can use to achieve this? Could you suggest techstacks or languages which have existing libraries that can help me do this, I explored discourse, firestorm, nodeBB however I am not sure if all of these support nested comments/ threads.