I manufacture and sell reversing camera kits for the Mk4 ND MX-5s. I don’t sell anything suitable for your car but can offer the following advice.
While the dome type cameras are perfectly suitable for the ND they don’t work well on the Fiat 124 which has a similar boot mount with a similar lip to the NC. The camera isn’t adjustable so the lip on the boot gets in the way. That’s why it has been previously suggested to use the 3D printed mount. A simpler solution is to use the type of camera which is cube shaped with an adjustable bracket. These are widely available on eBay and elsewhere. I supply these cameras to customers who wish to fit my kits to a 124.
Most aftermarket cameras are NTSC standard although PAL standard cameras are also available. If a listing doesn’t state which it is then it will likely be NTSC. NTSC cameras are the only ones which work correctly with the ND and 124 but make sure you have checked which you need for your Panasonic head unit.