Are ADC registers available for direct sampling?

Want to sample at ~100kHz. I can go lower if need be but my life is easier if I can get near this sampling rate.

I did this on the standard nano using the port registers was able to hit 150kHz (I think it can go higher, didn't check). I don't know what documentation/code I should be looking at if I wanted to pull this off. Would appreciate the guidance.

SOLVED!

The mbed-os core comes compiled so a lot of the implementation just isn't visible.

If you go to the actual github repo for mbed-os, you can see that they call the nrfsdk functions for the ADC (and other peripherals):

In the nrf sdk headers, they define the peripherals so you can access them without the sdk functions:

You will have to delve through the driver code to figure out how it all works though: