Nothing that we have a record of - if Tiberius thought or said anything about Jesus, there's no trace in the historical documentary evidence. There's no reason to think that Tiberius had anything to say about Jesus, given Jesus' relative obscurity in his own lifetime.

For a brief overview of the historical evidences on Jesus, see the faq, this will also cover what Roman evidence there is, and subsequently why there is no evidence to answer your question. See particularly

Is Tacitus the main reason historians accept Jesus's historicity? by /u/jasoncaspian

How much evidence is there for a historical jesus christ besides the bible? by /u/talondearg

What's the best evidence that Jesus did or did not historically exist? by /u/talondearg

In all likelihood, Tiberius never heard of Jesus. Our sources for the life an reign of Tiberius make no mention of the emperor knowing about him.

While we aren't certain what year Jesus was crucified, it is reported to have been under Pontius Pilate, who was procurator of Judea from AD 26 to 37. During that whole period Tiberius mostly lived on the island Capri (moving there from his villa at Sperlonga in AD 27.) So he was isolated from the goings on in Rome, His isolation was also used by his Praetorian Prefect Sejaus, who consolidated a lot of power for himself in Rome with the emperors absence, mainly because Sejanus was the only point of access to Tiberius. Tiberius called Sejanus the "partner of my labors," which along with many other aspects of his behavior during his reign leads us to believe that he didn't really want all the burdens of his office and was happy to let others take as much of the work off his hands as he could get. So unlike other emperors who were more "hands on" Tiberius probably didn't care a whole lot about what his provincial governors were doing on routine matters.

Finally Jesus just wasn't noteworthy in the least at the time. Judea was a provincial backwater in Roman eyes, and Jesus wasn't a Roman. From Josephus we know that there were many similar Jewish teacher figures leading small movements during the first century AD and Jesus was neither the first nor the most popular. Pilate himself was reported to have been involved in a number of incidents during his tenure as procurator of Judea and agitated the local Jewish population a few times. Pilate seems to be a bit harsh and resorted to forceful displays on a number of occasion it is reported, so his crucifixion of a nobody Jewish teacher accused of seditious behavior simply wasn't worth anybody writing to Tiberius about.