Forge load balancer 413 error on file upload

I'm uploading files to an s3 bucket, and have the max upload size set in forge for each of the servers behind the balancer, but I keep getting a 413 error whenever I try to upload larger files. When I point the DNS to one individual server it works, and I can upload the file successfully so I know the code works. I'm assuming it's trying to upload the files to the tmp folder on the balancer, but I'm no expert.

Should I go into the php.ini file and nginx config file on the balancer and change the max upload size or is there a better way to solve this problem?