You can now buy the Nike+ Apple Watch Series 3
https://www.theverge.com/circuitbreaker/2017/10/5/16431926/nike-apple-watch-series-3-for-sale
Apple has made the Apple Watch Nike+ Series 3 available for purchase today. As pointed out by 9to5Mac, you can pick up the Watch — which comes with a special Nike sport band or loop — online and in Apple Stores as well as at Best Buy, in both GPS and LTE variations.
It may be a bit tough to get your hands on the LTE version online, however: every model is shipping in three to four weeks. You can still purchase the GPS models and have them delivered this weekend, but if you’re looking for LTE connectivity (which Apple has recently fixed), you may have better luck trying to purchase one in an Apple Store or from your local Best Buy.