Indeed, in some of my own benchmarks, Caddy performed better than nginx in recent versions of Go. (Using "out of the box" configurations, anyway.) I know tuning is possible, as it is with Caddy depending on your situation. There are so many dimensions to performance of a web server, though, and I don't give much weight to benchmarks. https://gist.github.com/mholt/3f613740ceb417bf63fa
Googling around for a Caddy file[0], it looks fairly similar, and not so much easier or harder to configure or understand that NGINX config.
[0] https://caddyserver.com/docs/caddyfile