I set up everything from scratch on AWS and wrote a tutorial on it, I wouldn't do it again. It took me two months, even though I'm very technical I'd never done much Unix admin and no Nginx before.
If I did it again I'd use EasyEngine. You set up your server, run this, and it sets Wordpress and all required software (Nginx, caching, etc) up. I'd do it this way as it's a balance of control and automation.
Bitnami is likely fine. You can change just about anything on the install once it's done anyway.
Another important note is DO NOT use Amazon Linux. It works ok, but there's just not near the support or resources available for it. There's virtually nothing on Amazon Linux online, and you never know if it's Centos 5, 6, or 7 you need help with. I would use Ubuntu 16.04, which while new is built on a rich history and large community.