if youre just trying to change your chassis, any b15 sentra chassis is capable of bolting in your 1.8 motor/trans/suspension/etc. so any b15 chassis, which is 2000-2006.
if youre interested in just swapping the motor to a newer chassis, youll be looking for a 2002-2003 sentra xe, or gxe. this way it will bolt right in and your electronics will match up. the 2004+ is very similar, but quite a bit of electronic connections are different, so you may have to rewire stuff. im not positive about complications using the older 2000-2001 chassis, as the throttle is cable driven, which means you may need more parts from your old chassis, like gauges, maf, pedal, ecu, etc, and correct wiring since the old stuff isnt all electronic.
Aztec 02 Nissan Sentra SE-R Spec V, 270k miles
blown head gasket @153k, original clutch!
mods: optima, foglite mod, disabled auto a/c, dril/slot, es mmi's, jwt bsr, maf w/filter, catless header, ebay n1 catback, alum radiator, s.drives