Whether they were rewarded by actual merit isn't yet known. Their recent wealth is present-dated imaginary future gains paid by speculators. If by "merit", you mean the ability to perform skillfully to serve the whims of people with a lot of money, then yes.

Who is spending the kind of money that makes regular NVIDIA employees millionaires? You have to consider how those people attained it. And at the scale of NVIDIA's growing value downstream of a rapid investment in AI infrastructure, you can trace a good amount of it to Elon Musk, who has interfered illegally in an election to purchase favor with a party that ended several serious investigations into his companies. Now, the government is using Elon's AI which trails in several benchmarks. Elon's storied history of gaming systems to keep his companies alive only begins there.