Q: I'd like to use nginx distribution as part of my proprietary software package. How can nginx copyright be acknowledged when using nginx as part of a proprietary software distribution?

A: The text below should be added to your license conditions, followed by the text of the applicable 2-clause BSD license described here.

This product contains software provided by Nginx, Inc. and its contributors.

Also, if your build of nginx includes any of the following 3rd party products: zlib, PCRE, OpenSSL — it's worth including their copyright acknowledgements and disclaimers as well.