If you have a Nikon camera with a detachable lens but you do not know know the difference between a full frame and crop sensor, chances are you have a Nikon DX or cropped sensor camera. All of these cameras work fine for the aurora and there is not a substantial low light performance gap from the cheapest to the most expensive. If you are planning on picking one up, your best value, for northern lights purposes, will be in getting an inexpensive DX sensor camera and spend your money on a lens where you can meaningfully improve your low light performance.
The 7000 series does have one big advantage for shooting in the heart of winter, its battery. The batteries of the 5000 and 3000 series tend to freeze up easily so it is important to bring 2-3 spares to cycle them through out the night. With the 7000 series one batter is normally enough, even when it is cold (-20F or colder), but it is best practice to have one backup battery for it.
7000 Series Battery - Nikon EN-EL15c
5000/3000 Series Battery - Nikon EN-EL14a
Nikon DX Cameras with Mid-2022 Amazon Pricing
Most of the 3000 and 5000 series cameras come with a kit lens, the 18-55mm F3.5 lens like seen in the photo above. The kit lens can work for the aurora but it is difficult to manually focus in the dark due to no focus markings on the focus ring and it is at best, moderately capable for low light. You will have a vastly improved experience and photos by pairing our recommended lens below with your Nikon DX camera.