Supercharging is pretty simple. On the Frontier, the supercharger is about the size of a small loaf of bread, big enough to require Nissan to find an additional inch of clearance under the hood. It's connected to a belt at the front of the engine, just like a regular fan or power-steering pump. Ergo, more power. Aside from diesels, the only other supercharged or turbocharged pickup is the Ford SVT Lightning, which uses a supercharger to give racer-like performance to its big V8 engine.
Diesels use it to provide more power for towing and hauling.
The Frontier uses it to make you think you have a bigger engine, and it works. You can go from zero to 60 mph in about 9.8 seconds, which is maybe 1.5 seconds quicker than the regular V6 Frontier. On the road, the Frontier was pretty rough-riding on all but the smoothest pavement. Handling was a notch above the usual small truck, thanks to that stiff suspension and the big tires. On the other hand, those tires combine with the engine to make for a noisier experience than you might prefer.