Awesome refreshing salad! I usually double this and it is always devoured! Have used this recipe for 25 years. Hold off on cutting the avocado until just before serving.
Combine lettuce, chicken, black olives, green bell pepper, red bell pepper, and red onion together in a bowl; cover with plastic wrap and refrigerate until chilled, about 30 minutes.
Mix oil, red wine vinegar, lemon juice, sugar, salt, pepper, and garlic in a container with lid; cover and shake until well combined. Refrigerate until chilled, about 30 minutes.
Mix avocado into salad. Shake dressing and drizzle over salad; toss lightly.
Per Serving: 422 calories; protein 17g; carbohydrates 16.8g; fat 33.4g; cholesterol 39.4mg; sodium 945.4mg.