2002 Nissan Sentra Oil Pressure Light

It sounds like a semi-restricted oil pick-up screen. The higher the rpm's the more oil you need flowing through the engine. Enough oil can get through during low rpm idling or cruising, but when accelerating, not enough oil can get through. Drain the oil and remove the pan. (If the oil is pretty new, drain it into a clean container so you can put it back in later) You should see the pickup screen right away. It looks like a round piece of mosquito netting. If there is debris trapped in it then clean it out or replace it. If it looks clear then inspect the oil pump for gear wear. Also change the oil filter, it might be clogged too. If you notice a lot of sludge in the pan, then you might have a clogged oil passage. You can try to flush it out. If that doesn't work then you might need some major engine work.