So Google doesn't rely on Nvidia at all? How come they are the only ones that can manage to use non Nvidia chips and compete with Open AI?

Google's been making TPU chips optimized for machine learning and using them in data centers for almost a decade[0]. They were well-poised to capitalize on AI from a lot of angles.

0. https://en.wikipedia.org/wiki/Tensor_Processing_Unit#History

They offer Nvidia GPUs on GCP so they use them at some level.