The latest version of Tyk no longer requires nginx, which is why we made the decision not to include any nginx configuration settings in our latest user guide. You should still be able to use the configuration settings described in the older documentation but this is no longer a requirement.
I could not achieve having one domaine name for API requests and one domain name for the dev portal configuring Tyk. It was straightforward with nginx. Moreover, it allows me to add some custom url mapping for the dev portal.