You can’t impeach Nixon for trying to uncover corruption at the DNC’s Watergate offices. It was Nixon’s duty to fight corruption, and it’s not his fault that his political opponents were so corrupt that it required him to send burglars over to break in.
Some might counter that a President has better ways to fight corruption, such as sending in the FBI, whose job it is to do that. But Nixon is so passionate about fighting corruption that he felt compelled to secretly send his own burglars, loyal only to him, to get it done right.
It's disgusting that some think Nixon should be impeached simply for loving America so much that he just wanted to investigate corruption in the most effective way he could. You'd have to love corruption to criticize the Watergate break-in. It was a perfect break-in.