Help obfuscating access.log GET request parameters on AWS Elastic Beanstalk

I am trying to obfuscate a sensitive parameter that appears on some GET requests. These requests are encrypted, but are appearing in the access.log files in plain text.

I found this Stack Overflow question, which solves my issue... except that I don't configure nginx myself.
https://stackoverflow.com/questions/19265766/how-to-not-log-a-get-request-parameter-in-the-nginx-access-logs

I use AWS Elastic Beanstalk, which creates an EC2 instance running nginx. I have done literally 0 configuration of nginx myself, it uses default settings, including the default log_format.

I know that I have a file, `./ebextensions/nginx.config`, but currently it's contents are just this, to change the max body size of a request so that it's large enough to accept full res images from mobile devices:

```
files:
/etc/nginx/conf.d/proxy.conf:
content: |
client_max_body_size 5M;
```

I think I would be able to SSH into my instance to update this, but that would be overwritten with each deployment, and any new instance that gets spun up would still be using the defaults, so I think I need to figure out how to modify this from the file I posted above. However, I can hardly find any information on how to utilize this file.

Any help would be greatly appreciated!