Heat olive oil in a large pot or Dutch oven over medium-high heat.
Season chicken pieces with salt and pepper, then add to the pot and sear until browned and cooked through, approximately 6-8 minutes.
Remove chicken from the pot and set aside on a plate.
Add minced garlic to the residual oil in the pot and sauté for 1 minute until fragrant.
Pour in the chicken broth and bring to a rolling boil.
Add the penne pasta to the boiling broth. Reduce heat to medium and simmer, stirring occasionally, for 10-12 minutes or until pasta is al dente and most liquid is absorbed.
Stir in the Caesar dressing and grated Parmesan cheese until the sauce is smooth and coats the pasta.
Return the cooked chicken to the pot and toss to incorporate and reheat.
Remove the pot from the heat source. Fold in the chopped Romaine lettuce and top with croutons immediately before serving to maintain texture.