The world's top AI chipmaker is still selling the best picks and shovels for the AI gold rush.Nvidia (NVDA +1.65%), the world's largest producer of discrete GPUs (graphic processing units), became the world's first $5 trillion company on Oct. 29. Its market cap has pulled back to $4.4 trillion as of this writing, but it's still the world's most valuable company by a mile.Nvidia's stock skyrocketed 22,420% during the past 10 years, and that life-changing rally would have turned a $10,000 investment into $2.2 ...