Nope. Can’t happen. The Pope can excommunicate him if he’s teaching outside the scope of the Magesterium but he can’t defrock a bishop any more than St Peter could’ve kicked St Andrew out of the group of Apostles.
Why not?
Per Canon Law, Nieves can be dismissed from the clerical state and excommunicated.
But he can take away his rights to perform mass, hear confessions, etc.
Which is what will happen. He’ll do exactly that - call the archbishop to Rome. If the archbishop refuses to come then he’ll be excommunicated. He’ll appoint a new archbishop.