Bring a large pot of salted water to a boil. Add whole wheat penne pasta and cook according to package instructions until al dente, about 10-12 minutes. Drain and rinse under cold water to cool. Set aside.
While the pasta cooks, prepare the chicken. Pat the chicken breasts dry with paper towels.
In a small bowl, mix garlic powder, dried Italian seasoning, salt, and black pepper.
Rub the chicken breasts with olive oil and then evenly coat with the seasoning mixture.
Heat a large skillet over medium heat. Add the chicken breasts and cook for 6-7 minutes on each side or until the internal temperature reaches 165°F (74°C) and the chicken is cooked through.
Remove the chicken from the skillet and let rest for 5 minutes. Then slice into bite-sized pieces.
In a large mixing bowl, combine the cooked pasta, chopped romaine lettuce, sliced chicken, cherry tomatoes, green onions, and grated Parmesan cheese.
Add Caesar dressing and fresh lemon juice to the bowl. Toss everything gently until well combined and evenly coated with dressing.
Taste and adjust seasoning with additional salt and pepper if needed.
Serve immediately or refrigerate for up to 2 days before serving.