Nvidia is worth 42bn USD and employs 30,000 people.
Nvidia's has a market cap 30x of Intel's. So it could issue more stock to raise capital for a buyout. It's not the company equity but the market cap that it needs to have money to purchase. Even a controlling stake of > 50% would give them defacto control. Of course governments & regulators would probably block it or force Nvidia to divest bits of itself, and that's probably the greatest protection Intel has against such a scenario.
But if Intel weakens further, it may well be someone else tries to acquire it. I bet a lot of companies would love to snaffle it up. It's kind of ironic that Intel used to be the big dog in the semiconductor space but even AMD is bigger than it these days and are potentially many others who'd like buy it out. In fact, for all we know Intel might be shedding all these jobs to make it look more attractive to potential buyers.
The thing is that AMD and Nvidia are chip designers not chip makers. While Intel does design and print chips, the reason Intel is so critical (from US perception) is they own the foundries to make chips.
AMD decided years ago to go fabless, as for Nvidia I'm not sure they want to own the fabrication process.
Nvidia wants IP. They do not want to buy foundries. It's too volatile and dependent on government subsidies while also being well outside their core competencies. If their products don't sell as a fabless company, they don't see growth and lose on the manufacturing cost and stop placing orders. If their products don't sell and their chip fabs run idle, they lose a shitton of money on not just the above but also the cost of maintaining the fabs. Not only is there no guarantee that Nvidia would be able to run the foundries better, it's actually quite likely they'd run them worse.