Yes, you can vlog in a casino. There are no specific laws against it, and as long as you're not causing any disturbance, you should be fine. That said, there are a few things to keep in mind.
First, casinos are generally pretty dark places, so you'll want to make sure your camera has good low-light performance. Second, many casinos have a no-camera policy in certain areas, like the gaming floor or poker room. So you'll need to be mindful of where you're pointing your camera.
Finally, while most people are happy to be in a casino, some may not want to be on camera. So be respectful and ask permission before you start filming anyone.
With those caveats in mind, go forth and vlog away!