Both are smoother than regular cofee, but nitro cold brew is known for it's creamy, velvety texture.
Cold brew has a smoother taste due to it's long steeping process. Nitro cold brew has hints of sweetness.
Both are made by steeping coffee grounds for a period of time. But Nitro is pressurized with nitrogen using special equipment.
Cold brew looks like regular iced coffee, whereas Nitro has a cascading effect and foamy head, similar to draft beer.
Cold brew concentrate should be cut with water, ice or milk, whereas Nitro can generally be served on it's own due to it's nitrogenation and slightly sweeter taste.
You can easily make cold brew at home, and nitro cold brew can be made with the purchase of a special nitro cold brew coffee maker.