Hard to say without an actual link to the twitter post, but I suspect they followed the Curiosity/Ingenuity playbook here, creating a twitter handle that person

Hard to say without an actual link to the twitter post, but I suspect they followed the Curiosity/Ingenuity playbook here, creating a twitter handle that personifies the robot. Posts are made as if it's the actual probe/bot making the updates, in which case the sentence "... that it nicknamed..." makes sense.