Pat chicken breasts dry with paper towels, then season with salt, pepper and garlic powder.
Heat a large grill pan or skillet over medium high heat. Add 1 tablespoon of olive oil, then turn the heat down to medium. Add the chicken breasts, making sure not to crowd the pan. Cook until chicken is cooked through to 165℉, about 6-8 minutes per side. Transfer to a plate, and let rest for 5 minutes. (Alternatively you could cook chicken on an outdoor grill, in the air fryer or oven).
Salad
While the chicken is cooking, toss together the mixed greens and arugula and arrange on a platter or in a large bowl. Top with the cherry tomatoes, mozzarella, avocado slices and red onion slices.
Slice the chicken and arrange on top of the salad. Garnish with fresh basil.
Balsamic Dressing
Whisk together salad dressing ingredients in a medium bowl, or shake together in a sealed mason jar. Set aside.
Drizzle balsamic dressing over the salad just before serving.
Notes
Store any undressed leftover salad covered in the fridge for up to 2 days. Already dressed salad will not keep well because the greens will become wilty.