Even if Nvidia is sued for being a monopoly, does it really matter? Intel pretty much had a monopoly for 10 years. The US government did nothing and they still have yet to pay their EU fine, which was only a fraction of the money they squeeze out of the market.
I highly doubt the US government will do anything, they are insanely pro big corporations. Heck, the companies and CEOs pay a lower tax rate than a middle class American. The amount of wealth held by the 1% was extremely bad before their tax cut, after it's a plutocracy. Trickle down economics is just a renamed economics system that's been in place since the age of monarchs.
Even if the EU fines them, it will be too little too late. The amount Nvidia could make will likely far exceed any fine.