Cook and dice the chicken breast, then allow it to cool.
Wash and dry the lettuce and vegetables thoroughly.
Chop the lettuce into bite-sized pieces.
Slice the cherry tomatoes, cucumber, and red onion.
Place the lettuce, vegetables, chicken, and shredded cheddar cheese into a large salad bowl.
Drizzle ranch dressing evenly over the salad.
Toss gently until all ingredients are well coated.
Garnish with fresh parsley or cracked black pepper if desired.
Serve immediately or chill for 15 minutes before serving.