Well, I doubt that the Massassi's ranged weapons would do squat against the Yuuzhan Vong's vonduun crab armor. The same can't be said for the Vong's amphistaffs in relation to the mutations' skin. However, some of those bigger Massassi would easily be able to smack around the lesser Vong warriors for a while, at least until they get WTFmobbed.
I'd say the Vong take this; they have superiority in numbers and technology, as well as additional cavalry in the form of voxyns and those tank-like beasts.
The Massassi don't just use ranged weapons. Actually, those disc throwers appear to be combination axes.
And the situation of this battle needs to be stated more clearly. There are far more Vong than there ever were Massassi, are we just assuming that we throw all of the ones to ever exist against each other or are they given comparable forces?