If you till this mulch material in to your soil then it will be a soil amendment and while wood chips are ofetn used as soil amendments they can create some short term problems with plant growth such as tying up Nitrogen so it is not available to the plants. That does resolve itself in a few months depending on how active the Soil Food Web is in your soil.
You have no planting beds to puit this mulch on?

I assume from your screen name you are located in OR :-) Unless you are laying sod, in our area it is advised to wait until fall (September/early Oct) to put in your lawn. If you were to incorporate your pile of wood chips into your soil now and keep the area moist, you should have a pretty decent seed bed for a new lawn by the time it is recommended to plant.

I would try to make sure any large pieces were not included or chipped to make smaller. I'd also apply a starter fert after seeding just to be on the safe side (re: the N issue). 15 yds is a LOT - use only what you need to improve the soil in the new lawn area and use the rest to mulch planting beds or to help prepare new planting beds.