yeah, i finished platinum but i still EV training giratina. To catch a good nature is pretty easy, its a matter of reseting.
But, i recently relayed pokemon XD gale of darkness. And OMG i got a modest lugia (atk down, sp atk up). And some of you know its got the exclusive move psyco boost. Really lucky since you can 't see the nature of shadow pokemon. and it automaticly saves if you finished the game.
Yeah, the Chancey I caught in XD was Bold nature, luckily, and getting Chansey's in 3rd gen games are VERY HARD, considering it's that or the safari zone, in which they're near impossible to catch. And the 3rd gen games are the only ones where you can get them seismic toss, which is a pretty essential move for competitive battling Blissey's.