What did the Supreme Court request from Richard Nixon that would implicate him in the Watergate scandal?

The supreme court requested that Richard Nixon hands over the tapes that he had. If they had them, they could then see what he's done and how corrupt he was so he decided to resign before being impeached. That's why he's not on the short list of presidents who were almost impeached, the other two being Clinton and Jackson, both of whom were acquitted of charges.