"管理" is empire-building

He saw more work coming down the pike.

He wants to be a 2nd-line manager.  By hiring Nattie, he removes himself from the daily grind, and Nattie proves to him that she is able to do the dirty work.  If she pushes over a couple of apple carts, so the better, time for reorg.

Complaining to your manager is not much of a help.  Managers are a clique.  As long as management meetings go smoothly, there is always some emplyee complaining, which can indicate the managers are good overseers (of the plantation kind.)

For your self, have an identity other than your job.  So when Nattie says something is wrong with your work, you would not take it as an assault on your dignity.  She may even insinuate toward that direction, but you wil not follow her there.

When someone says something to you, do not just stop at what she said.  Ask why she said it.  Then you give yourself more time to deal with it calmly.  She wants you to focus on what she said, and you prove her success by becoming upset by what she said. 

Next time reply to her: I'm OK with the change you asked.  You must have a reason for such change.  Would you mind letting me know your reasoning? So that I may learn a thing or two.

She wants you to take her seriously, and so far she has been very successful at it, because you offered resistance which provides her power.  When someone charges toward you, the better way is not to block her, but get out of her way.

Bonnie starts shaking at the sight of Nattie is because Bonnie's fight/flight trigger tells her to run, but her upper brain tells her she cannot.  Tell Bonnie to read this book "Snakes in Suits."  She may feel better afterwards.