Normally I like to do manually job.
assume that the default path of your nginx cache is /var/cache/nginx
find /var/cache/nginx -type f -delete
This will clear all your cache in one line.
Delete a single file from nginx cache
If you just want to delete a single file from nginx cache, you can try this.
grep -lr '//juzhax.com/wp-content/plugins/jetpack/modules/wpgroho.js' /var/cache/nginx*
Then it will show something like this
You can safely remove by using rm