To clarify the frequencies used by nanoVNA for the various measurement ranges I made a small table.
So if you are measuring in band 1 (300-900MHz) the CH0 output is actually a square wave of a lower frequency (1/3) and the 3rd harmonic is used by mixing it with the 5th harmonic of the mixer LO input
As of band 1 and higher the output power of CH0 is increased with 12dB to compensate for the lower energy in the 3rd harmonic.
Be aware as the strong fundamental may overload some DUTs such as amplifiers or mixers
Maybe something for the wiki?
