Intel is 100% committed to x86 and nvidia is 100% committed to ARM. In the mobile space, buying nvidia only makes sense if Intel wants to reduce competition, but Nvidia is still very small compared to other players like Qualcomm and Nvidia is probably competing more directly with Qualcomm than Intel anyways so a double knock on this rumor is that Intel would probably want Nvidia to stay around to keep clawing at Qualcomm.
On the desktop / server / hpc side, Intel has spent years and billions on hundreds of engineers developing their own graphics as well as a standalone hpc accelerator, it just does not make any sense.
3-4 years ago, as Larrabee showed signs of failure and Intel had zero mobile market share, this would have been credible. Now? Not at all.