Remember the Emoluments Clause of the Constitution? Nobody even thinks of it any more. But this is an impeachable offense, one of hundreds in the last year. And by the way, can anyone reconcile the USSC immunity ruling with the Emoluments Clause?

The Emoluments Clause is not a criminal provision. Like everything else in the Constitution, violating it is not a crime. If you believe the phrase "high crime or misdemeanor" in the Impeachment Clause refers to actual criminal violations, not merely violating the Constitution, then accepting an emolument would not be grounds for impeachment. Since every President ends up having something they do found to be unconstitutional at some point, it's probably a valid distinction.

It's also worth noting that the Emoluments Clause only prohibits the President from receiving things from foreign governments and heads of state - it doesn't apply to gifts from private individuals. Machado is not currently a "King, Prince or foreign State," and cannot realistically be argued to be acting on behalf of the Venezuelan government - especially since the Nobel Prize was something awarded personally to her, not the country of Venezuela as a State. So, Trump probably didn't violate the Emoluments Clause by accepting her gift.

As for the USSC decision, it's the same thing. The SCOTUS ruling only held that the President is immune from criminal prosecution for acts in office. It doesn't immunize him from civil legal proceedings to enjoin or enforce a violation of the Constitution. Since violating the Emoluments Clause isn't a crime, the SCOTUS ruling doesn't apply. [Note: the President also cannot be held personally liable for damages in civil suits for actions taken in the performance of his office, but that was the law well before the current SCOTUS].