How can I modify the nginx configuration in Railway?

Hi! I'm getting a "413 Request Entity Too Large" when uploading photos to my deployed app. How can I modify the nginx.conf file in Railway to change the client_max_body_size variable?

I've already posted this question on stackoverflow with no answers: https://stackoverflow.com/questions/76216476/how-can-i-modify-the-nginx-configuration-in-railway

Any help will be really appreciated!