Nginx https to http server - php

Question

I have a PHP application(docker) + nginx. This server I access through https. But my problem is, I have the same application(updated version, same routes) in another server that I don't have an https or a public address. Is it possible for nginx to "redirect" to this new server but using the url of my current application/server until I don't have a public ip?
etc/hosts file
172.14.0.3 app // docker ip
# xx.xx.x.xxx app // new server ip
127.0.0.1 my_app_url.com
# xx.xx.x.xxx my_app_url.com // this is the new server IP I was testing
my nginx file, on the proxy_pass property, I was passing the new server ip
server {
listen 80;
server_name my_app_url.com;
location / {
proxy_set_header HOST $host;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_pass http://app;
#proxy_pass http://xx.xx.x.xxx; -> I was testing
}
}
server {
listen 443 ssl http2;
server_name my_app_url.com;
ssl on;
...
...
...
ssl_dhparam /etc/nginx/ssl/dhp-2048.pem;
location /.well-known/acme-challenge {
root /<app-path>
}
location / {
proxy_set_header HOST $host;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_pass http://app;
#proxy_pass http://xx.xx.x.xxx;
}
}
I tried to make these alterations, but I don't know if it's possible and acceptable to do this.