Where can you find a diagram for a fuse box for 1992 Nissan sentra?

First of all take off the fuse panel inside the car. It's to the left of the steering column on the lower part of the dash. If you need more than that, a Haynes or Chilton's Manual is your best bet. As I have one right here, I'll try to relay the info. From the top left, and listing straight down, they are:

1&2: 20Amp Rear Defog

3: 15A Fuel Pump

4: 10A Engine Control

5: 15A Stop Lamp

6: 10A Tail Lamp

7: 10A Air Cond.

8: 10A Dome Light

9: 10A Electronics (Connected to battery)

10: 15A Fog Lamp

11: 10A Hazard Lights

Back to top right

12&13: 15A Blower Motor

14: 10A St. Signal (not sure what that means)

15: 10A Audio

16: 20A Wiper & Washer

17: 10A Power Mirror

18: 15A Cigarette Lighter

19: 10A Airbag (if equipped)

20: 10A Electronics (connected to ignition)

21: 10A Turn signals

22: 10A Meter

If you need the actual wiring diagrams, with this fuse going to that wire and so forth, you must invest in a manual from any auto parts store. It's so freaking useful, I buy one for every car I own.