GPIO input tolerance when Arduino powered via 3.3v pin?

Hi

If I power nano every via 5v, then understandable that GPIOs are 5v tolerant but I need to power Arduino nano every using 3.3v power. Will Arduino nano every GPIO digital input support still 5v? Any documentation to ground this answer?

Thanks in advance

No

The data sheet for the nano every says it works from 5v , it has an in board regulator to produce 5v from higher input voltages.
I can’t see how you would operate it from 3.3v , if you could then I would not expect the inputs to be 5v tolerant as the input protection diodes would become forward biased and feed back into the supply rail .
If you google nano every you can get the spec of the board, you can also google processor to get its spec - if this is like the Atmel 328 then it would run at lower voltages if the clock frequency were lowered , but a UNO can’t work at 3.3v