Here's the thing: I share your worries Yolo, but I think Buffalo is just a bad matchup (or good for us) vs the Niners.
Chip's offense (for the 3 years I watched it in Philly) is brilliant when everything is clicking at the same time. Kaep, at his best, is near unbeatable when clicking.
But they are flying cross country and playing in a very hostile stadium. Kap's biggest knock was accuracy and a difficulty reading defenses. Chip Kelly needs accuracy with all his high tempo pick routes. Rex (with Palmer and Brisset) got back to swarming amoeba coverages. And when Chip goes 3 and out, he goes 3 and out fast.
Also, unlike last year vs the Eagles, their run defense is putrid. I don't care what the score is in the first half, pound that rock.