I don’t believe so (Sitchin is Jewish).
That said, it seems Sitchin and his followers don’t realize how his ideas open themselves to that charge. How? Aside from pure imagination, a lot of Sitchin’s ideas presuppose a dependence of the Hebrew Bible (Old Testament) on earlier Sumerian and Babylonian literature. More acutely, Sitchin asserts over and over again in his books that the Old Testament writers borrowed their material from the Sumerian and later Mesopotamian people.
This idea was all the rage in the late 19th century and early 20th century, particularly in the wake of the famous “Babel und Bibel” (“Babel and the Bible”) lecture of Friedrich Delitzsch. It was the era of the decipherment of cuneiform and the discovery of creation and flood stories in Mesopotamian literature. It was also the era of deepening anti-Semitism, a belief cultivated nowhere more zealously than Germany, Delitzsch’s fatherland. In fact, it was in this environment that the “higher criticism” of the Bible began. The criticism of the Bible as in any way historical was led by German anti-Semites. The result was the pursuit of alternative origin stories, found ever-so-conveniently in the writings of the “Aryans” (who supposedly came from Sumeria — is this sounding familiar, ye followers of Sitchin?). The Nazis, of course, made this dogma, since the “Aryan” (Vedic) writings were written in Sanskrit, which was the ancient ancestor of Indo-European languages, of which German was prominent. Yes, they descended from the gods who first gave kingship, the right to rule, at Sumer — unlike those inferior Jews. They and their myths had to be eradicated.
As I’ve told Sitchinites at various lectures, no credible OT scholar today argues that the Genesis stories came wholesale from Mesopotamian material. That idea is passe, but Sitchin doesn’t seem to mind being 100 years behind the curve. The literary issue is far more complex than what we think of as borrowing, and people who spend time in the biblical text know it, and so have abandoned the views of Delitzsch and his followers.
For a readable (non-specialist) discussion of how Delitsch’s anti-semitism fueled his scholarship, click here [from Bible Review 18 no 1 (F 2002): 32-40, 47]. Amazing how this despicable bias influenced generations, and is still influencing amateur researchers like Sitchin, though only sub-consciously.