Tesla has to show that Zoox is using the information the employees allegedly stole. In a nutshell, Tesla would have to show similarities between its logistics processes and Zoox's. (https://www.fenwick.com/FenwickDocuments/Trade_Secrets_Prote... for a good summary)
But given the shitshow that is Tesla's logistics , that's extremely unlikely, as Tesla's logistics processes simply aren't valuable IP. Tesla has displayed a chronic inability to manage their own supply chain, especially during the period the employees were at Tesla. If anything, Zoox used the information allegedly taken from Tesla as an example of what not to do logistically, and trade secrets law doesn't let you sue for that.
EDIT: To clarify: there are 2 lawsuits in the article. One is against an employee for stealing trade secrets, which doesn't require proof that his new employer is using the secrets. That lawsuit doesn't involve Zoox. The other lawsuit is against Zoox and former Tesla employees for using Tesla's trade secrets. I'm only referring to the one against Zoox. It's pretty clear that the secrets were misappropriated, so the real question is whether those secrets are actually being used.