Viltrox will release a new AF 28mm f/4.5 pancake lens for Nikon Z-mount on May 20th. The lens already exists for Sony and Fuji cameras – see the full lens coverage here.
In the US, Viltrox lenses are sold at B&H Photo. International shipping is available from Pergear and the official Viltrox website. You can get 8% off at the Viltrox online store with the coupon code NIKONRUMORS: