If you read to the end of the article it addresses the GM deal. GM will use its own battery tech. Nikola is basically just sales/marketing. The deal still makes absolutely no sense, but GM isn't dependent on Nikola having working tech or not.
If Nikola is an unexpected success, then they have a significant stake in it, and if they fail, then hopefully they don't have too many vehicles that Nikola hasn't paid for.
GM can definitely build a good electric vehicle. They cannot seem to market a good electric vehicle—see Chevrolet Bolt sales, and then ask a random person if they know what a Bolt is. So the Nikola investment is the equivalent of buying a hip design studio?
In the worst case, they were paid to do their own R&D.
Nikola basically bribed GM with a insane deal so they can say they have a GM partnership.