According to a user on Reddit, it's possible to get support for Google's Daydream VR platform onto the Nexus 5X, and potentially other devices which are running on the Android 7.0 Nougat software. Having said that, this isn't official support from Google or the manufacturers so there is no guaranteeing that it will work for any phone or device that has Android 7.0 Nougat software installed. It's also worth mentioning that some users may have varied results compared to the original poster even if they are running the same device, although that is much less likely if all of the same steps are followed.
If you're interested in giving this a try, the first thing that will need to be noted is that root access is required for this to work, so if you don't have a rooted device, you're still stuck without Daydream VR support. For those that do have rooted devices, the next step is to open up any file explorer application that will let you see and navigate through the folders that are only visible with root access. The file that users should be looking for is "/system/etc/permissions/handheld_core_hardware.xml" without the quotes, then add <feature name="android.software.vr.mode" /> and /> <feature name="android.hardware.vr.high_performance" /> lines into the root permission tag
After that part of the file has been modified, all that should be required is a phone reboot to implement the changes, and from here you should be able to install the Daydream app, as well as apps that were designed specifically for Daydream VR and utilize the Daydream View headset. While the original poster on Reddit only mentions this working for the Nexus 5X, a user in the comments states that they were able to get it working on their LG V20 as well, which of course came running on Android 7.0 Nougat out of the box. That being said, users with the Nexus 6P, or any other device that's running on Android 7.0 Nougat can give the method a go as long as their device is rooted. Eventually other manufacturers will put out devices that come with Daydream support out of the box, but the selection of devices is a little bit limited at the moment.