补充：直接按本文修改可能会引发错误，详见文章 针对 nginx 中 add_header 指令的层级继承所引发的问题的分析与解决

将原来的

add_header Strict-Transport-Security "max-age=63072000; includeSubdomains;

增加一个协议判断即可

if ($scheme = https) {
     add_header Strict-Transport-Security "max-age=63072000; includeSubdomains; preload";
}

注意放在 location 块内

add_header

Syntax: add_header name value [always];
Default: —
Context: http, server, location, if in location