It seems like the rumors weren't all wrong, Nvidia does, in fact, already have an x86 processor and it's listed on their Website. It's called the M6117C and it seems to have been part of the package when Nvidia bought ULi.

However, we doubt that any of the x86 processor manufacturers will feel any kind of threat when it comes to the M6117C ,as it's a 386SX based core which is available from 25 to 40MHz. This is a single chip solution for embedded computing and the 386 core is paired up with the ULi M1217B chipset in a single package.

We're not sure if this means that Nvidia has some kind of x86 license, or if this is just something that is a leftover from when ULi was a chipset manufacturer and had a demand for a low-cost embedded solution and it just got transferred into Nvidia's product range.

Even if Nvidia was to have some kind of basic x86 license, this wouldn't mean that Nvidia could make a modern x86, or even less so a 64-bit x86 CPU, but one can't help to smirk at the irony.

You can find the product page here