Not sure if you mean
A: to stop the problem from happening ("FIX")
B: or looking for a way to overcome it ("WORKAROUND")
If A, then you need to find a command that works to reload NGINX when a cert is renewed or find the reason it is failing; start by removing the --quiet.
If B, then you have many options... You could introduce an additional cron job that can reload/restart NGINX at any interval less than the time between the latest renewal and the expiration of the currently in use cert.
It renews by default.
It does not reload the web service by default.
But your cron job shows the inclusion of:
which is how certbot would try to reload nginx when a cert was renewed.
So we need to understand why that call fails.
For that, please show the output of: sudo /usr/sbin/service nginx reload
Or if there are any other errors preventing that call from even being executed.
For that, we can remove the --quiet from the cron job and review the logs after it runs (without it).