What is better? NIPT OR NT SCAN?

Jen
So I realized on my appointment paper it says I am scheduled for a NT SCAN. and honestly,i know it's not what I want but what insurances covers and what doctors prefer. But I don't want to get so many sonogram some I rather get blood and let them test whatever they are looking for. Which is better out of the two?? Does the NT SCAN also include blood test? And which test is more accurate ?