okay one thing is - my favourite interpretation of Nisha is as someone who doesn't rig the game. That she can take an L -> because to her, most of the things she does would not make sense and not be exciting if she couldn't lose (aka die a horrible death).
I think it's important to keep in mind that the things Nisha does, they don't really have an endgame, the way Jack's plans for example do. She also doesn't really want to accumulate anything. And while I think she takes some sadistic pleasure in being infamous and feared, being famous also isn't a goal in itself.
What she really wants is a) constant thrill and excitement b) getting better and better. That's something that comes up in her lines a lot - she wants to fight 'real badasses' and she wants bigger challenges all the time.
There is generally a pattern of gamifying things with Nisha. The whole 'she got good at catching things because of all the things her mother would throw at her' -> tbh i think the explanation is a bit silly, but I do take it as Nisha's perspective on things, at least in hindsight; That her mother's abuse is something she started interpreting as a challenge and that it made her 'better'. Just like in her perspective, killing the dog she loved made her better because it also taught her to overcome something that held her back.
The opposite to that is her father - for her, that's what 'weakness' is: Avoiding challenge, avoiding conflict, not getting better.
(I think that's another aspect that imo is important to Nisha which is her very specific brand of self-discipline. She's not a military character-archetype like Athena for example. In fact, in many ways she is very self-indulgent and hedonistic - we know she drinks a lot, she is not exactly a professional on her jobs (I actually think that when she first met Jack, it was more of a 'recreational' interest before he went off the deep end and became actually interesting to her).
What I mean with self-discipline is that while ramping up the violence and the challenges, she is effectively avoiding a lot of introspection and thinking about any deeper meanings. Being scared, being sad, grieving, hoping, empathy - those emotions are something she often had to deal with as a child. So for her, that's a child-thing. So when other people actually allow themselves to feel things - or are overwhelmed with them - in Nisha's eyes, that's being childish. That's weakness, that's lack of discipline. That's embarrassing. (That's her dad...)
In her world-view, she actively ended all of that when she ended the life of her dog as a child. So the moment someone gives a shit about something trivial or sentimental - in her eyes, they're just weak and pathetic and they are going to die anyway. If anything, it's her right to crush whatever they cared about, make them watch - and then they either kill her or she kills them.
(Another take i have on her is that lack of challenge and lack of growth also directly leads to her sadism goes into absolute overdrive - and I think that's what happened in Lynchwood. Sure, I think she's a sadist in all fights she's in. But at the end on Pandora, she is no longer going up. She is no longer fighting vault monsters or even trained enemies. She is back to 'flaying bandits alive on Pandora'. So I think what she does is that she becomes more and more sadistic and vicious out of sheer boredom and also, to create more opportunities for whatever fighting and conflict she can get out whatever enemies she can find.)
