First, prepare vinaigrette. To a large bowl, or resealable bag, add ¼ cup of vinaigrette, chicken breast, salt, pepper and garlic. Toss to coat well. Marinate for 1-2 hours.
While the chicken marinates, make the bacon. Once done, allow to cool and roughly chop. Set aside.
To a grill plan, add 1 tbsp olive oil (make sure it is for high heat) on medium high heat. Once hot, add chicken breast, grill for about 6-8 minutes, and flip, cooking for 4-5 more minutes, depending on thickness (should be 165F).
Remove chicken from pan and allow to rest 5 minutes. Chop and set aside.
Divide lettuce between four plates then top with chopped bacon, tomatoes, chopped avocado, and chicken. Serve with additional dijon vinaigrette.