Wikipedia says:
James' instructions included several requirements that kept the new translation familiar to its listeners and readers. The text of the Bishops' Bible would serve as the primary guide for the translators, and the familiar proper names of the biblical characters would all be retained. If the Bishops' Bible was deemed problematic in any situation, the translators were permitted to consult other translations from a pre-approved list: the Tyndale Bible, the Coverdale Bible, Matthew's Bible, the Great Bible, and the Geneva Bible.
So the Tyndale Bible is definitely one of the references the KJV translators used, but it doesn't say how much they used. I don't know if it qualifies as "a lot" but I'm sure there's at least a bit of Tyndale's material in there.