This will get fast-tracked through an appeals court system. Even our jacked Supreme Court has to concede that states do not have the power to restrict federal elections like the presidency.
Let me start by saying I don't agree with the passing of this law. But...
Have you read the Constitution? Here's the section of Article II that deals with selecting electors (i.e., members of the electoral college). Emphasis added.
Each state shall appoint, in such manner as the Legislature thereof may direct, a number of electors, equal to the whole number of Senators and Representatives to which the State may be entitled in the Congress: but no Senator or Representative, or person holding an office of trust or profit under the United States, shall be appointed an elector.
If you have any doubts, read the majority decision in
Bush v Gore, where the state legislatures are shown to have total control over the selection of their electors.