Thanks for posting. Let's take a look at why you're not able to play a video from your Google Photos to your Nest speaker but before that, it would help a lot if you could clarify some things first to narrow things down. Do you have the Google Home Max or Nest Hub Max? Is that a speaker type or a display type? Also for confirmation, you're trying to play a video which is saved on your Google Photos app to your Nest device, right? A video that you took using your phone's camera or a video downloaded from a music platform?
Looking forward to your responses.