Place lettuce in a large bowl and top with tomatoes, bacon, cheddar cheese, and sliced avocado.
In a small bowl, whisk together mayonnaise, Greek yogurt, lemon juice, Dijon mustard, garlic powder, and chives. Gradually add milk until dressing is your desired consistency. Taste, and season with salt and pepper as needed.
Drizzle the dressing over the salad and toss well to combine. Serve immediately.
Notes
If using store bought dressings, ranch or blue cheese pair well.
Dressed salad will keep for up to 1 day in the refrigerator.