NIPT, while still being only a screening, not a diagnostic, has fewer false positives than the Nuchal test.
The woman who did my blood draw and sonogram for our NIPT was actually one of the people on the panel that recommended the Nuchal test to the NHS back in the late 90s/early 00s. At that time, they recommended ten measurements be used in the scan, but the NHS only uses three of them. This became fairly standard in the early 2000s.
She said she'd like to see NIPT completely replace the Nuchal because it is more accurate switch fewer false positives and far fewer false negatives than the Nuchal.
Both tests are only screenings though. Amniocentesis and CVS are the only diagnostic tests that can give certainty, though they carry risk.
Nuchal and NIPT are meant to be used to help us decide whether to do an amniocentesis.
The woman I mentioned above said that NIPT is often the next step AFTER an at-risk Nuchal test result, and she even encouraged me to only do the NIPT to avoid the anxiety that mixed results can create.
Only you can know if you are comfortable going by the NIPT probabilities or if you wish to proceed with an amnio/CVS.
It may be down to whether doing the amnio would affect your decisions or not. There is no right answer here.
I'm sorry that you're faced with this decision and I'm sending you hugs and support. 🌻