Main problem is that the soil micro-organisms which ultimately break down the chippings have to 'borrow' nitrogen from the surrounding soil because the chippings themselves contain little or none.
This can lead to temporary nitrogen depletion - not what you want when growing crops with high nitrogen requirements.
As Potterer has suggested, this is not really a problem if the chippings are used as a mulch (i.e. they can't 'suck' nitrogen out of the soil beneath them.)
I'm guessing that the chips would likely be from pine trees, which do produce more organic acids during the decomposition process than some other materials, but the consensus 'out there' seems to be that the effect on soil pH is very small, and in any case when used as a mulch they will only decompose very slowly.
I would only be slightly mindful of it if I knew my soil was already a little on the side of being too acidic.