Nixon tried to do what Trump is doing now: he wanted to get out wars, he wanted to eliminate bureaucracy, he wanted to rein in the intelligence agencies, and he wanted to return a lot of power to the states. That's why they did him dirty. Nixon spying on his political opponent was the justification.
He did spy on his political opponent, but guess what? LBJ spied on Goldwater, Eisenhower spied on JFK, and so on. Nixon won 60% of the popular vote and smashed McGovern in 1972, so there was no way for members of Congress and the media to undo Nixon's mandate without some absolute horseshit. Never forget that Bob Woodward was a Navy spook and Carl Bernstein was a literal who. If anything, Watergate was more about John Mitchell, the Attorney General, but the powers that be exploited it to oust Nixon. It was a shot across the bow to every politician since not to mess with the embedded bureaucracy or the US intelligence community.