Preheat oven to 400°F 

Begin by lining a heavy sheet pan with aluminum foil or parchment paper.

Next, arrange the chicken breast pieces in the center of the sheet pan.

Next, add 2 tablespoons of vegetable oil to a small bowl and use a brush to coat the chicken pieces then season with Creole seasoning (or your preferred seasonings).

Next, prepare the vegetables by cutting the yellow squash and baby potatoes into chunky pieces then add them to a mixing bowl.
Next, remove the stems from the mushrooms and add the caps to the mixing bowl. Discard the mushroom stems or freeze for making stock.

Next, add 1/4 cup of vegetable oil to the vegetables and toss to coat with the oil then season with salt, black pepper and dried thyme. Give the vegetables a toss once more to coat with the seasonings.

Next, arrange the vegetables on the sheet pan around the chicken breast pieces.
Place the sheet pan into the pre-heated oven and reduce the oven temperature to 350°F.

Bake 35-45 minutes. The internal temperature of the boneless chicken breast should read 165°F and the vegetables should be tender.