To leverage the .nft.json files emitted to the .next output directory, you can read the list of files in each trace that are relative to the .nft.json file and then copy them to your deployment location.
Automatically Copying Traced Files
Next.js can automatically create a standalone folder that copies only the necessary files for a production deployment including select files in node_modules.
To leverage this automatic copying you can enable it in your next.config.js:
next.config.js module.exports = {
  output: 'standalone',
}
This will create a folder at .next/standalone which can then be deployed on its own without installing node_modules.