Native is such an abused word.
You can literally use all of the iOS SDK directly.
Not sure why I'm downvoted.. https://old.nativescript.org/native-api-access/
It's the basis of their entire product. On top of that they've built cross-platform wrapper for many UI things. And on top of that, they've integrated several toolkits.
They just market it the other way around, which i.m.o. is not helping them with traction. Right now they're always competing with many other products (react native for example), even though they have a very unique product.