Android in Google Pixel is said to offer better experience than the UI in Nexus but these are the few reasons why there isn't much to note about the differences.  

-       There are new features that arrive on Nexus

The Support tab and camera user-interface are a few of upgrades exclusively made for Pixel phones (except Daydream VR support). However, these aren't exclusive. Ars Technica has learned that even the Smart Storage is available in Nexus devices when upgraded to Nougat.

-       A slightly redesigned app drawer won't hurt

Google made a few tweaks on the App drawer. The result has made Pixel devices sleeker with a clean screen appearance after the apps are hidden at the bottom until user swipes it up.

@AndroidPolice did those icons use to turn black in #pixel launcher app drawer? pic.twitter.com/sS29a5IMGA

— Harshad Kale (@kalehv) January 19, 2017

-       Voice assistant isn't necessary

The one exclusive feature available in Pixel UI is the Google Assistant. This is apparently a major change coming to the smartphone as it is intended to manage daily schedules and more.

Digital agent is having a moment and it may be a cool thing to learn that someone can control almost everything from a smartphone using their voice. However, research has shown that voice command isn't widely used, according to Technology Review. Only 6 percent of consumers use voice assistants in public and 1.3 percent at work.

With that being the case, Google Assistant is a good addition to the device but there are probably people who prefer Google Now on Nexus devices that doesn't require them to speak loudly to request something.

The Android in Google Pixel phone offers a clean design but that doesn't mean that Nexus isn't. There are indeed, a few differences but not a totally different platform.