Season the Chicken: Pat the chicken breasts dry with paper towels. Season both sides evenly with garlic powder, salt, and black pepper. Lightly coat the chicken with olive oil.
Cook the Chicken: Heat a large skillet over medium heat. Add the seasoned chicken and cook until golden brown on both sides and cooked through, about 6–8 minutes per side depending on thickness. The chicken should reach an internal temperature of 165°F.
Remove from the skillet and let the chicken rest for 5 minutes before slicing.
Make the Honey Mustard Dressing: In a small bowl, whisk together the honey, Dijon mustard, mayonnaise, lemon juice, olive oil, minced garlic, salt, and black pepper until smooth and creamy.
Taste and adjust the honey, mustard, or lemon juice to your preference.
Prepare the Vegetables: Wash and thoroughly dry the salad greens. Halve the cherry tomatoes, slice the cucumber and red onion, and dice the avocado.
Assemble the Salad: Place the mixed greens in a large serving bowl. Add the cucumber, cherry tomatoes, red onion, and avocado.
Slice the rested chicken and arrange it over the salad. Drizzle with the honey mustard dressing and gently toss just before serving.