In a large bowl. whisk together all of the dressing/marinade ingredients: balsamic vinegar, olive oil, garlic, Italian seasoning, light brown sugar, salt, and pepper.
Place chicken in a shallow bowl and pour 3 Tablespoons of the dressing/marinade over the chicken; set the rest of the dressing/marinade aside. Turning the chicken on both sides, coat with the dressing/marinade and allow to marinate for 10 minutes.
While chicken is marinating, set out the mixed greens on a large salad bowl or serving platter.
Then cook the chicken on a grill pan over medium-high heat for about 7-8 minutes on each side, until cooked.
Allow chicken to rest for 5 minutes before slicing.
Arrange the cooked bacon crumbles, tomatoes, red onions, radishes, avocado, and sliced chicken over the mixed greens. Sprinkle feta cheese. Pour dressing/marinade over the salad and serve immediately.
Notes
Makes approximately 4-6 servings. Store salad separately from the dressing for up to 3 days in an airtight container in the refrigerator.