are snow chains allowed for the 4x4 with p265/70R 16 tires?

Snow chains should work on those tires. I recommend that if you are using snow tires you should get a set for both the front and rear. There are pros and cons to putting chains on both the front and rear but in the end it is better to put the chains on the rear. You will lose a little steering capability (steering would be better with chains on the front) but the chains on the rear of the car would prevent you from fishtailing which is the main concern when driving in the snow.