Season the boneless, skinless chicken breasts with salt and pepper. Heat 1 tablespoon of olive oil in a skillet over medium heat. Cook the chicken for 6-7 minutes on each side until cooked through.

While the chicken cooks, bring a large pot of salted water to a boil. Add elbow macaroni and cook according to package instructions, about 7-8 minutes until al dente. Drain and set aside.

In a medium saucepan, melt 3 tablespoons of butter over medium heat. Whisk in 3 tablespoons of flour and cook for about 1 minute. Gradually whisk in 2 cups of milk and continue whisking until the sauce thickens, about 3-4 minutes.

Reduce heat to low and stir in 1 cup of shredded cheddar cheese and 1 cup of shredded mozzarella cheese until melted. Season to taste with salt and pepper.

Fold the cooked macaroni and shredded chicken into the cheese sauce. Mix in ½ cup of BBQ sauce until evenly coated.

Serve hot, drizzled with additional BBQ sauce and garnished with fresh herbs if desired.