I think you are confusing an executive order with a regulation issued by a department or agency. Congress can’t override an exec order, but they can take it to court.
Congress has the power to overturn a regulation OR executive order by passing legislation that invalidates it. Congress can also refuse to provide funding necessary to carry out certain policy measures contained with the order or to legitimize policy mechanisms. In the case of the former, the president retains the power to veto such a decision; however, the Congress may override a veto with a two-thirds majority to end an executive order.