A couple of possibilities

Why AOC Doesn’t Want Trump Impeached

These are only a few of the lawmaker’s calls for impeachment; if we were to document them all, it would likely fill the entire library of Congress. But why is Ocasio-Cortez so adamant about pushing the Democrats to pursue this course of action? After all, it is unlikely that the myriad investigations being carried out by the Democrats will turn up any piece of dirt that would persuade a Republican-controlled Senate to vote for conviction and removal of Trump. Is it possible that the representative has an ulterior motive?

She could simply be uneducated about the impeachment process.

But, more likely,  she needs a Nixon type to do MMT. Liz Warren will not figure this out before the election and no one believes Liz will do MMT.  Trump already has a clue.  AOC's best shot at getting the MMT moment is for a desperate Trump to pull one of those Nixon Shocks. 

If Liz attempted this we would have a year of meetings and a thousand precious government goodies that need protecting. Nothing would happen. Trump has no priors, he is perfectly fine with a Nixon style MMT.