Well to be honest, i do prefer to do everything in NativeScript, and like you mentioned almost 80% of you application is going to be in NativeScript and with it, you have the following :
1 - it is truly native, you can call Native API directly from the SDK, and also from 3rd party libraries (any 3rd party library you want), something will be easy and feels and taste the same way as any called "native" app will do.
2 - Cross platform application ( just think of how much time you will take is you go with "Native" path)
3 - Developing a Game beneath an app, is actually easy using nativescript and typescript ( in case you wanted to make things interesting )
4 - You have the power of JavaScript, AngularJS, you name it, everything will be in javascript, so thats means that you can even port your web application ( in case you have such thing ) directly to your application.
5 - In case of an game, if you read or follow or searched over the nativescriot.org site you will come across this wonderfull article about incorpotaring games into your next application using Physics and even the accelerometer over here : https://www.nativescript.org/blog/details/first-steps-in-game-dev-with-nativescript.