Nvidia's explosive growth has propelled CEO Jensen Huang into the upper ranks of global wealth.Bloomberg/Getty ImagesNvidia is worth nearly $5 trillion, but billionaire investor Dan Loeb says the AI giant is still undervalued.Loeb, the founder of hedge fund Third Point, says investors are underestimating Nvidia's earnings power.Wall Street has made similar mistakes with Amazon and Google in the past, he said.Stock market darling Nvidia is worth …