here's the repository Nodebb-plugin-elasticsearch
Since the current nodebb search engine seems not to support Chinese-text search, I choose the elasticsearch as the content, post and topic, search engine.
I found nodebb-plugin-search-elasticsearch but the original author doesn't maintain it anymore. I made few modification of it.
Before doing searching, remember to start elasticsearch and import your data from the original Nodebb-supported database, mongodb/redis ,to elaseticsearch to build index by any plugin you use. (I am using mongo-connector.)