Can the US Supreme Court overturn a Presidential veto?

No. Creating and vetoing laws is part of the legislative process, which is the responsibility of Congress and the President, respectively. The Constitution does not grant the Supreme Court any power to make law or to override a veto.

If a law is successfully passed, then challenged in court, the Supreme Court can determine whether the law is constitutional under their right of "judicial review," and can nullify the law if they determine it to be unconstitutional, but that is the extent of the Court's formal involvement in the legislative process.