It really matters what kind of wood chips you're trying to use. The wrong sort can doom your gardening project.
Wood Chips, Sawdust and Bark Chips
Wood chips and sawdust from large diameter limbs, trunks and Evergreen trees kind of suck the nitrogen out of any environment they're used in. Their Carbon/Nitrogen ratio can run from 400:1 to 750:1. It has to do with the decomposition process and the bacteria and fungi that decompose wood. They need nitrogen to create protein and will remove it from the soil to try digesting the woody materials. Evergreen content also introduces a lot of tannins, substances that are used by these trees and shrubs to control plant growth underneath their drip-line and can stop plant growth till they've been broken down by soil bacteria.
Usually composting wood chips works best if you take something with so much nitrogen content it will burn plants (chicken manure) and mix the two together to compost both into a usable soil amendment.
As a mulch, wood chips can be effective, just don't till them into the soil for the above reason. Rake off at the end of the year, sow your cover crop for over wintering.
Ramial Wood Chips
True Ramial Wood Chips are supposed to be new growth, small branches and tree top wood from deciduous brush and trees with the diameter not to exceed 7cm/2.75". The name comes from the Quebecois term "bois raméal fragmenté" or in English, "chipped branch wood". This is all from the parts of the trees and brush that are still growing, contain soluable unpolymerized lignins and high quantities of nitrogen, phosphorus, potassium, magnesium, calcium in the cambium and bud tissues.
Because of the Carbon/Nitrogen ratio in Ramial Wood which averages 30:1 and if larger diameter branches are included can go up to around 170:1, we're dealing with a much different product from wood chips. The various studies in Ramial Wood agriculture often add Blood Meal (about 13% Nitrogen) to add a little extra nitrogen to the mix to make up for the higher Carbon/Nitrogen ratio in the larger branches.
Why Ramial Wood Chips work:
You are starting off with a nutrient rich mulch that has a high content of unpolymerized lignins and enough nitrogen to not deplete the soil. The unpolymerized lignins require no breaking down to become a ready food source for soil fungi that quickly absorb it and proceed to break the rest of the wood content down into soil humus. This also starts liberating the nutrients that beneficial soil bacteria require.
If you're growing fruit trees you will find Ramial Wood Chips to be a ground mulch that also provides nitrogen in an ammonia based process due to the soil environment it creates, a source of nitrogen better adapted to tree growth. Shrubs and trees prefer ammonia, not nitrates.