Certain Wall Street experts are predicting substantial losses for shareholders of Palantir Technologies and Nvidia.Palantir Technologies (PLTR +1.65%) and Nvidia (NVDA +0.03%) have been two of the most popular artificial intelligence stocks since ChatGPT launched in November 2022. During that period, Palantir has returned 1,960% and Nvidia has returned 1,290%. But certain Wall Street analysts think the stock are overvalued.Brent Thill at Jefferies recently raised his target price on Palantir to $70 per shar ...