By its moniker alone, you can safely assume the Nova Plus is the oversized version of the Nova. In reality, they don't have too much in common, at least not on the outside.
You can safely look at the Huawei Nova Plus as the international version of the G9 Plus. The 5.5" display is of 1080p resolution, and while the front looks similar to the Nova, the back is another matter entirely. It's made of aluminum as well, but the camera has a bump and is placed in the center, right above the fingerprint sensor.
The camera itself is a 16MP unit with optical image stabilization, dual-LED flash and 1.12µm pixel size. It can also record 4K videos with ease.
Update: We managed to snap a few camera samples with one of the IFA units:
The chipset is similar to the Huawei Nova, but has 4GB of RAM and thanks to the larger body the battery is a 3,340mAh unit.
Expect the Nova Plus to become available sometime in September with a €429 price tag.