Reverse Proxy url mantaining same domain url

Question

I'm trying to insert an iframe SITEB into SITEA

SITEA:

<iframe src="SITEB"></iframe>

SITEB does not allow iframing, so I would like to reverse proxy it with nginx on an internal url. Like SITEA/iframe -> that points to SITEB

Is something duable with nginx?

I tried with this (using google.com as SITEB):

But this redirect to Google.com

server {
  listen 80;
  server_name sitea;

  location / {
    proxy_pass  http://google.com
    proxy_set_header Host google.com;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-Proto $scheme;
    proxy_hide_header 'x-frame-options';
  }
}

how to use a reverse proxy to get around X-Frame-Options: SAMEORIGIN for iframe

Any hints appreciated.