Bald spots on the abdomen are pretty normal with defensive T's like this one that kick hairs often. As Jake mentioned it's a bit overweight so you can slow down on the feeding a bit. Otherwise I wouldn't worry too much.
I fully agree with Jake and Lloyd.
I had 2 N.chromatus, and they both loved flicking for the slightest reason.
So they permanently walked around looking like that.
As long as the T does not look to be in distress, everything is normally ok.
You will probably see with the next molt it will be gone.
Also with the feeding, maybe try feeding every second week or so till it lost a bit of weight
The substrate in your first pic looks a little wet, maybe try drying it out a bit?
If you have a water bowl there is no reason really to wet the substrate, I used to keep mine almost bone dry, with just the water bowls
The white might just be some discoloration, or a bit of chafing from scratching, or a dry bit of skin from a previous molt
Like I said, if the T does not show signs of discomfort, 99.9 percent of the time it is nothing.
You got nothing to worry about she is A ok promise. Read up on new world tarantulas vs old word tarantulas, then you will know whats up with her. She has a bit of hair loss next molt it will all be back and more. Enjoy your spider and relax.