That's not possible as Nvidia got out of the mobile phone space, they are sticking to tablets and handhelds. The subtext of that is they do not integrate cellular basebands, making it way less efficient in a phone which would require a separate chip compared to a Snapdragon. Qualcomm's 64 bit all in one is the 810 due in Q1 2015, which compared to the competition will be more than the saying of a day late/dollar short.
This is actually not true. Back in the Spring they confirmed Android 5 would be 64 bit (on proper hardware obviously). The new ART runtime is 64bit, Dalvik is dead. There's no emulator yet because there's no hardware for developers to test it on yet. This Nexus 9 with whatever Nvidia chip will be the first in that dark side of the world.