Nomad Outfit is a skin for the Hazmat Suit item in Rust. You will be able to apply this skin at a repair bench or when you craft a Hazmat Suit in-game. It was one of the first skins released on the Rust Permanent Store, an update by Facepunch to offer untradable skins for sale to players for a longer period of time rather than the weekly releases.
The Nomad Outfit can currently be purchased on the Permanent Rust Item Store. As the name suggests, it will remain permanently unless Facepunch decides to make any adjustments.
No, this is a cosmetic item tied to your Steam account. While it will be visible in your Steam inventory, it cannot to be traded to other players or sold on the market.