The hair: Nick has black hair, slicked to the side.
This Jacket: Nick hons a White formal jacket to compliment his white pants and blue shirt. This can either be a very cheap or very expensive part.
Shirt: Nick wears a simple light-blue formal tucked into his pants.
Pants: Nice white formal pants, but don't forget to add some dirt and blood.
Shoes: (as far as i can tell) Nick wears normal brown casual shoes.
Weaponry: Nick's favorite weapons seem to be the Sniper Rifle, AK-47, and Submachine Gun. The Sniper Rifle is actually a Heckler & Koch G3 with a scope. Most airsoft G3's will be expensive, and scopes are usually extremely expensive. The AK-47 is a common airsoft. You can probably get a cheap electric one for around twenty bucks. For the SMG, you can just use a simple Uzi. If you want to make the Silenced SMG, you can get a Mac 11, suppressor, zipties, and a flashlight. Just smack the silencer on the Mac, then ziptie the flashlight onto the supperssor or handguard.
Hope this helped.