Great setup!
Nordic specifies this in the datasheet:
An antenna inductance of Lant = 2 μH will give tuning capacitors in the range of 130 pF on each pin. The total capacitance on NFC1 and NFC2 must be matched.
if its 130pF per capacitor for 2uH, surely it will be higher for 1.4uH as inductance is in the denominator?