Inside Nikola — the one-time Wall Street darling mired in controversy

The last few months have been a roller coaster ride for battery and hydrogen-powered semi truck maker, Nikola. Initially, the company briefly surpassed Ford's market capitalization. A partnership with GM further bolstered Nikola. But with founder and former executive chair, Trevor Milton, now facing fraud and sexual assault allegations and the GM deal up in the air, CNBC decided to visit Nikola's headquarters to find out what is really going on with the one-time Wall Street darling.