The Nanoleaf remote is able to connect to H-A over Bluetooth as a HomeKit device, but it doesn’t emit any events beyond battery and signal strength updates. It does have a “button” entity, but it’s for identification (makes the remote light up.)
Looking at the event stream, it doesn’t appear that anything is dispatched when the remote is rotated in the horizontal plane, placed on a different face, or shaken. These are events that are picked up by the actual HomeKit on Apple devices.
Could these events (or an appropriate entity to track the current top face) be added to the device? It’s not usable as a remote currently.