Wood in any form uses nitrogen in the decomposition process. The process
involves bacteria that digest the wood. The bacteria also require air
and water, so the process only takes place on the surface of the wood.
For that reason, large chips will use less nitrogen than finely divided
wood chips or sawdust. If your wood chips are from a chipper (which is
mostly what I see being used as wood chip mulches), they will most
likely not extract nitrogen from your soil at a rate that will harm your
plants. Since you're placing 6" of chips in with 8-10" of soil mix and
compost between them, you should have no problem unless your planter is
filled with things that have a really large root system.

If you're talking about sawdust, on the other hand, I would put it into
a compost pile and add vegetable scraps for a year or so (turning
occasionally). That will make compost, which you can use anywhere.