Pat the chicken dry and cut it into evenly sized pieces. Toss with olive oil, garlic powder, paprika, onion powder, oregano, black pepper, salt, and lemon juice.
Heat a large skillet over medium-high heat. Cook the chicken in a single layer, turning as needed, for approximately 6–10 minutes or until it reaches 165°F (74°C) internally. Cook in batches if necessary.
Transfer the chicken to a clean plate and allow it to rest briefly.
Wash and dry the romaine. Chop the lettuce, dice the cucumber and onion, and halve the tomatoes.
Whisk together the Greek yogurt, light mayonnaise, Dijon mustard, lemon juice, optional honey, garlic powder, and black pepper. Add water gradually until the dressing reaches your preferred consistency.
Divide the lettuce, cucumber, tomatoes, and onion among four bowls. Top with equal portions of chicken and the optional cheddar.
Drizzle each bowl with one-quarter of the dressing and serve immediately, or keep the components separate for meal prep.