Add all of the ingredients, except the 2 tablespoons of olive oil, to a large mixing bowl then stir together until everything's evenly combined.
3 boneless, skinless chicken breasts, 2-3 medium zucchini, 2-3 medium yellow squash, 12 oz white button mushrooms, salt & pepper, 3 tbsp minced garlic, 1/3 cup olive oil, 1/4- 1/3 cup soy sauce, 1 1/2 tbsp rice wine vinegar, 1 tbsp sesame oil, 1 tsp garlic powder