To use Nightfall.ai integration in n8n, start by adding the HTTP Request node to your workflow canvas and authenticate it using a generic authentication method. Once connected, you can make custom API calls to Nightfall.ai to query the data you need using the URLs you provide, for example: after setting up the HTTP Request node and authenticating, you can create records by sending a POST request to the Nightfall.ai API endpoint for new entries, including the necessary data in the payload. For updating records, use a PATCH request with the record ID in the URL and the updated fields in the body. To retrieve data, a GET request to the specific endpoint will return the desired records for further processing in your workflow.