Official cookbook to install kibana 4

I am looking for a chef cookbook to install kibana. I did find kibana_lwrp but it installs ngnix and stuff. This brings me to another question.

Why do i need ngnix with kibana. Most of the articles i find online talk about using ngnix with kibana. I am going to use it inside an internal network, do i really need ngnix ? I played around with kibana after installing it locally and looks like it has a built in webserver. That looks good enough to me.

You don't need nginx, KB will run perfectly fine by itself.
Some people like to proxy things with it, some use it to provide basic auth.

This cookbook seems to be for Kibana 3, which did not have a server component. Kibana 4 does as you point out come with a built in web server and does not need nginx.