Using 3.3v for ICSP programmer
Some programmers supply power to the target device, some do not, and some have a switch or jumper to select it. This varies on a programmer-by-programmer basis and you will have to examine the documentation and/or schematic of the programmer to verify.

Additionally, you must not apply 5V to any pin of a 3.3V device unless it is strongly current-limited in order to avoid burning out the pin's protection diodes.

And furthermore, not all AVRs actually support programming at 3.3V, so read the "Memory Programming" section, "Serial Programming" subsection of the datasheet for the device before attempting to do so.