Prepare Wish-Bone® House Italian Dressing & Seasoning Mix according to package directions, using extra virgin olive oil and balsamic vinegar. Reserve 1/2 cup prepared Dressing & Seasoning Mix; refrigerate remaining for another use.
Grill or broil chicken, mushrooms, and tomatoes, brushing with 1/4 cup reserved prepared Dressing & Seasoning Mix, until chicken is thoroughly cooked, mushrooms are tender, and tomatoes are charred slightly and ready to burst, about 15 minutes. Slice chicken.
Toss arugula with remaining 1/4 cup reserved prepared Dressing & Seasoning Mix in salad bowl. Top with chicken, mushrooms, and tomatoes. Garnish with cheese.