Q.Do I have to remove wood chips from deep in the ground before planting flower and ground cover garden?
Had a thirty foot Sweet Gum tree cut down. Stump and large roots were chipped and left deep in soil. If I don’t dig and remove the chips will it effect the new plants I plant? I need to create a Sun garden where we had a shade garden.

You have a legitimate concern. If the sweet gum was removed this year, the stump grindings/ wood chips that remain below the soil grade will still be relatively "raw" and will require heavy nitrogen use for the decomposition process. If you plant in that spot your plants may suffer from Nitrogen deficiency. Other than digging the grinding out and replacing with new soil, you can apply a pound or two of high nitrogen fertilizer, Ammonium sulfate 21-0-0 or Urea 46 -0-0 , water it well and give it a month or two for the chips to start decomposition before planting.