Apple watch didnt come with charger in box

Any mains power adapter with a USB socket for the cable will work fine. If you bought an Apple Watch you probably have a charging adapter for your iPhone which will do the job. Even a computer USB port has more than enough power to charge a watch.

That one only includes the cable. On the watch page for that watch this is stated under “what’s in the box”:

5W USB Power Adapter

(GPS + Cellular model only)

Should include one, does it have a cutout for where the adaptor should go to?

Nike Apple Watch Series 3 Unboxing - YouTube

also i dont think Apple is selling the Series 3 Nike+ version are they?

Apple UK is still listing Nike Series 3, presumably remaining stocks mist go. https://www.apple.com/uk/shop/buy-watch/apple-watch-series-3/space-grey-aluminiu m-anthracite-black-sport-band?preSelect=false&product=MTF12B/A&step=detail# and agreed it should have a charger-power adapter based on that page.