Tacitus explicitly refers to a "Christus" crucified by Pilate and the cult followers he gave his name to, "Chrestianos," distinct but related to Judaism. If there is a problem with citing him as proof of Jesus's historical reality it's that he doesn't tell us where he heard about "Christus," and might just be reporting the claims of the cult without having bothered to see if Prefect Pilate actually executed a random Hebrew cult leader for treason.
Of course, by the time Tacitus wrote he might just not have bothered, rebelling against Rome and getting executed for it is just kind of what Hebrews did at the time.