Xiaomi is Accepting Beta Testers for a MIUI 7 Build for the Nexus 5

If you have a Google Nexus 5 and you’re interested in trying out MIUI 7 (which is based on Android 6.0 Marshmallow), then you’ll want to head over to the MIUI forums right now and apply to be a beta tester. You’ll need to be somewhat active in their forums before you can apply to beta test the ROM, though.

source: xdadevelopers