Season the chicken breast with salt and pepper.
Roast the chicken breast in the oven at 180°C for 20 minutes.
Peel the potatoes, cut them into large pieces, and steam them.
Slice cucumber, lettuce, and avocado into bite-sized pieces.
Cut the roasted chicken breast and potatoes into bite-sized pieces.
Combine all ingredients in a bowl and toss with olive oil and lemon juice.