The LG Nexus is a very bad kept secret. Everyone even remotely interested in Android known that it exists. The phone which has the codename Mako, now has been benched using the GLBenchmark scoreboard, and it sure is a very fast phone, as now it is one of the world's four fastest devices. Ofcourse, all four of the top four devices (Pantech Vega IM A850, Asus Padfone 2 and Xiaomi MI 2) are running a quad core Snapdragon S4 and Adreno 320 GPU.
The benchmark also clearly states that the phone is running Android 4.2.
The benchmark can be checked here.
Source.