Season the chicken breast evenly with garlic powder, sea salt, and black pepper.
Heat a grill pan or skillet over medium-high heat and cook the chicken for 6-7 minutes per side until the internal temperature reaches 165°F.
Remove the chicken from the heat and let it rest for 5 minutes before slicing into thin strips.
In a small glass jar or bowl, whisk together the extra virgin olive oil, lemon juice, finely chopped parsley, and chopped dill to emulsify the dressing.
Dice the cucumber, halve the cherry tomatoes, and thinly slice the red onion.
Place the mixed baby greens in a large serving bowl and layer the cucumber, tomatoes, and onion on top.
Add the sliced chicken and the avocado slices to the bowl.
Drizzle the lemon-herb vinaigrette over the salad and toss gently to coat all ingredients before serving.