Your domain cannot be reached by Let's Encrypt using HTTP. The --nginx authenticator uses the HTTP Challenge method and your domain must respond properly to the http request.
The Let's Debug test site is helpful when starting a new site.
After studying your log more I also see that you don't have any server blocks defined in nginx. You should review the nginx docs about that. But, at minimum, you should have a server block for this domain name with at least this:
server {
listen 80;
server_name vps.niceatc.com.br;
#root /your/default/webserver/folder;
}