According to the documentation, the Business plan should have access to NAT Rate Limiting. However, the fact that you only see "IP" in new Rate limit rules on your Business plan account suggests that there might be a UI issue or a discrepancy between the documentation and the actual feature availability.
If the issue persists, you may want to reach out to Cloudflare support to investigate and clarify the availability of NAT Rate Limiting on your Business plan account.
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