The question is based on the following setup.
As depicted there is an IC to measure the real value of the 3.3V supply voltage accurately. The measured value of the 3.3V source is transferred via SPI to the microcontroller. This microcontroller is measuring the voltage divider between 3.3V and GND and has a reference voltage for its ADC.
simulate this circuit – Schematic created using CircuitLab
Problem: If the 3.3V supply voltage is changing the ADC measurement from the microcontroller is influenced.
Question: Can I compensate a changing 3.3V source with the measurement of the IC if the accuracy if this chip is within my limits.