This battle will basically comes down to this: can nagato absorb or push kamui using preta or deva?
Kamui is a ninjutsu, so one could say it gets absorbed. However, it doesn't have a physical form. in fact, the jutsu works by opening a worm hole connecting kamui dimmension to the very point the user is looking at, and with this, the oponent is "sent" to kamui.
At the same time, how can nagato push this kind of atack, based on the mechanics?
The way I see it, nagato wouldn't be able to push it, but perhaps he would be able to absorb the concentration of chakra in that spot, because the energy used to open a worm hole is kakashi's chakra, so MAYBE he could so something.
But it's very hard to decide.