This does sound awfully like ARFID and given the genetics for ND are there, I wouldn't be so quick to say she's NT.
From an adult ARFID sufferer, who went through all the varieties of parental pressure to eat that ranged from 'harsh' to actually abusive...
- Offer several safe foods at every meal
- On a totally seperate plate, make available whatever other option there is (ie what you're having).
- Say NOTHING at all about trying it, about it being nice, and if she does try it, again say absolutely fuck all. Nothing. Zip it.
In essence, take the pressure right off, and respect when she has what may seem like odd whims, ie a particular brand of chicken nuggets being acceptable/unacceptable, or things needing to be cut smaller or prepared in a certain way.
Ignore anyone telling you to just offer what you're having or nothing, kids with ARFID will absolutely starve themselves to the point of serious weight loss and needing a feeding tube.
Don't try to hide food in safe foods, thats a rapid way to lose a safe food!
Praising attempts to try stuff usually backfires, most children, by the time they're noticably struggling with food, will read this not as genuine praise but as you telling them 'look, see you WERE being silly, it IS nice really, so you were wrong, your opinion isn't important'.
Negotiating ARFID as an adult can be hard, there have been times I have been so hungry I am in tears but there isn't a single thing I can stomach, and I can buy whatever the hell I like!
When you're a kid, and you don't know whats wrong, and you don't have the language to explain it, and you're trying to explain these things like 'the texture of that potato reminds me of a time I was sick and then I feel sick then I start gagging' or 'having my mouth slightly too full with large pieces of food or having to chew for too long makes me feel physically sick and I stop being able to swallow whats in my mouth'... thats hard. Trying to explain it to an adult who patently does not believe you because they have never experienced these feelings/sensations themselves, impossible really!
Lots of folks with ARFID are also supertasters (not all, because ARFID can be about shape/size/texture/appearance as well as flavour) - so for us, what tastes fine to you can be massively overpowering to us. Or we can detect underlying flavours you can't - I can pick up when DP has not rinsed the dishes well enough, I can tell the type of potato used and when we've moved from the old bag to the new bag, I can tell if the milk is about to go off two days before it actually goes off.
You can do a supertaster test strip (they taste horribly bitter to supertasters, very mildly bitter or like nothing at all to normal and non-tasters) which will tell you very quickly who in the family is or isn't!