Let's get physical!
Oftentimes character shrines will have needlessly detailed write-ups chronicling every bit of a character's physical appearance, thus proving just how much of a sad fangirl the webmistress is. This is one of those times.
First, let's talk about Nash's Suikogaiden outfit. It is very uh, billowy. He wears a scarf over some kind of coat-cape thing over a weird donut fastener thingie over a yellow tunic. Below the belt, he's wearing a, er, kilt. Konami would like you to belive that it's just an overcoat of some kind, but seeing as that it's at once over and under his tan shirt. Thus, it seems to be in two pieces- the coat part at the top, and the skirt part at the bottom. His shoes are kind of uncomfortable looking and square shaped. No wonder the official art shows him everywhere with Grosser Flux to make him look badass. But Nash's outfit, if a bit on the HAHHAHA ARE YOU WEARING A DRESS?! side, is at least practical. You can't go wrong with layers!
If we remove the billowy overcoat/mandress factor, we see underneath that Nash's fashion sense is no less disturbing. The gloves hid something more complex and weapon-like. He opts for the manly shade of lavendar, and that what first appeared to be normal pants are in fact some sort of elaborate blend of tights and garters. Also of note is the hidden backpack and how darn tight everything is. Nash seems to like leather straps and needlessly complicated fastening devices. I can't come up with any reason for a donut-like fastener for the life of me.
However, as he grew older, his clothing got less strange.
Nash's Suikoden III outfit is much simpler. It doesn't billow, for one thing. He wears a dark shirt, a coat, a pair of khaki pants, some hiking boots, and of course, the scarf. The jacket is the most striking part of the outfit, being more than one color and piped with white. Around his waist, instead of his duel snake swords, is a simple dagger. There's still a spike launcher up his sleeve, though, and that, not the dagger, is his primary weapon. (He does draw the dagger on several key occasions though.) Perhaps he's trying to keep a lower profile, or maybe his clothing tastes tend toward less fancy stuff in his old age. Heck, maybe he just got hot with all those layers in the grassland. In the manga, he wears chainmail underneath his coat.
One notices that Nash has a tendency towards earth tones. And, uh, lavender.
Obligatory Section About Hair, I Choose You!
Nash's facial features are narrow and angular, with a tendency towards the pretty boy especially in his youth. Nash is the scion of a destroyed aristocratic Harmonian faction. So, he was born a first-class citizen, and like all first-class citizens, he has blond hair and blue eyes. He wears his wavy hair long in the front, but short in the back, in a kind of reverse mullet I have dubbed the tellum. In Suikoden III he cuts it a little bit and parts it more on the side, but it's essentially the same hair style. Nash's eyes, despite the first class Harmonian blue requirement, change color more than the early Final Fantasy characters change their hair.
These are all unaltered color samples I've taken from Nash's eyes.
Notice that they are really blue almost none of the time. In the Suikogaidens they're an aqua color with tendencies towards green, in the gaiden FMVs they're grey, in his Suikoden III stautus portrait they're a grey-blue color, but in the actual game they look almost brown. He has too many character designers, or something.