For Z32: Gran Turismo 3 A-spec, yes, as well as both older GTs, and no doubt the new GT4. GT Concept has the 350z in too, I think... don't know whether any GTs have the S30 in though :/
Then there's the Penny Racer games - Penny Racers, Gadget Racers, and Road Trip Adventure - this last one is the best, it's an RPG featuring cars for all the characters
You trundle around a massive landscape looking for other cars to race or trade items with. It has both Z32 and S30 body shells
(probably a Z31 too, not sure... there's hundreds of shells to choose from :S). The cars are super-deformed, like toy cars, hence the name "Penny Racers", and the feel is kind of "kiddie" (so if he'll hate that, maybe best to avoid), but they're fun and quite challenging
Then there's Tokyo Xtreme Racer Zero (drive around the Tokyo ring road looking for rival racing gangs, then come home and spend your cash on cosmetic and performance upgrades). Meh, it doesn't look as good as the TXRs on Dreamcast but it'll do
Features Z32, and an unlockable S30 (the S30 was the ultra final car in the first game on DC!). There are later TXRs available, I think, and they'll have Zeds in for sure, but I know nothing about em :/
And Auto Modellista - a slick cel-shaded (i.e. anime-type cartoony) JP racer - straight from the start you can grab yourself a Z32, paint it a sick combination of colours, and smother it in stickers. Very stylish game, with tons of tuning options and branded mods, but not as long as GT3, or as deep as TXR, and I'm not sure if it has an S30 in... :/
Driving Emotion Type S has a Z32 in as well, but it was an early title for the PS2, wasn't well-received even at the time, and has somehow kept its price quite well (all the above, apart from the Gran Turismo games, can be got for a tenner or less if you buy pre-owned). I've not played it, but friends tell me the handling is bizarre... not one I'd recommend
That's all I know for now... The first Need for Speed: Underground and Midnight Club didn't have Zeds in, but the sequels *might*, and for some reason the hardcore JP drifting games (Initial D, Battle Gear/Tokyo Road Race..) don't seem to feature Zeds, although they'd be the perfect style for an S30. I bought another, Road Rage 3, today... not tried it, but doubt it will have a Zed in
These games are great if you like the JP touge-style (twisty mountain roads) racing, but tend to be arcadey in structure.
In short, recommendations for Z32 games:
Gran Turismo 3
Tokyo Xtreme Racer
Auto Modellista
Road Trip Adventure - also features S30! And most other drool-inducing cars you can think of!
Shame he's not getting XBox, then he'd have access to Sega GT 2002 (and the Online version), which gives heavy respect to all generations of the JP heavies - Zed, RX-7, Skyline, Supra, Celica. Features S30, Z432, a G-nose... *drool* ... also has novelties like the Nissan Mid-4 concept, and the "Zero" supercar
Hope that helps some... if not, specify what gen of Zed you're interested in, age of said nephew, how much you're wanting to spend on how many games... (I'm not good with present type things cos I tend to buy all my games dirt cheap second hand, plus I like tacky obscure stuff, neither of which will go down well here, I suspect :S)