The NGINX Ingress Controller for Kubernetes is an alternative Kubernetes ingress controller that can be used instead of the default ingress controller.
From NGINX website:
The NGINX Ingress Controller for Kubernetes provides enterprise‑grade delivery services for Kubernetes applications, with benefits for users of both NGINX Open Source and NGINX Plus. With the NGINX Ingress Controller for Kubernetes, you get basic load balancing, SSL/TLS termination, support for URI rewrites, and upstream SSL/TLS encryption. NGINX Plus users additionally get session persistence for stateful applications and JSON Web Token (JWT) authentication for APIs.