I have brought a now tv box and am reading through various online guides to add plex to it. Once that is done if i am streaming some sport on my mac desktop can i stream it to the tv my now tv box is connected to ?
If you have a channel in Plex for the content your streaming you should be able to. If you are just streaming in your web browser then i dont think you will be able to.
No you cant do that on the Now TV box, you can watch various Sky Sports channels which i'm presuming you would probably pay extra for. List of apps on the Now TV: Available apps: (NOW TV Box) | NOW TV - Help