Do you have numbers on that? Google was one of the largest manufacturers in the world for a couple years there. It wouldn't surprise me if they were still up there.
They've also already been building their own network chips for some time. So, given the scale of their datacenters, I think it's entirely reasonable that they'd outpace nvidia.
There are such an insane number of processors being made, we have Apple, Amazon, AMD, Nvidia, Google all buying their stuff from TSMC. I would be very surprised if Google was the biggest of them all.
[1] https://www.wired.com/2012/07/google-server-manufacturing/