Pence can look at Pennsylvania (or any) and decide, "Oh wow! That's a substantial amount of fuckery. Let's just pretend Pennsylvania (or any) doesn't exist this year."

So Pence can choose Dem or Rep electors, if boths' electoral certificates are submitted (which is the case in some states.) Or he can just decide NOT to accept any electors from a contested state. Because, according to the Constitution, that is his legal right as President of the Senate.