The Cisco Nexus 9300 Series switches are a family of high-performance data center switching products. However, only a specific subset of models within this series supports 400-Gbps Ethernet ports.
Based on the information available online, two models from the Cisco Nexus 9300 Series that offer 400-Gbps Ethernet ports are:
Cisco Nexus 9316D-GX: This is a 1RU fixed switch that provides 16 ports of 400 Gbps (QSFP-DD) with a non-blocking switch architecture. It's suitable for aggregation, core, or spine applications.
Cisco Nexus 93600CD-GX: This is also a 1RU fixed switch, but it offers a combination of ports. It includes 28 ports of 100G and 8 ports of 400 Gbps (QSFP-DD) with a non-blocking switch architecture. This model is well-suited for data center Top-of-Rack (ToR), End-of-Row (EoR), and collapsed aggregation and access deployments, particularly when used with Cisco Nexus 2000 Fabric Extenders.
Reference:
Cisco Nexus 9000 Series 400G Deployment Guide