Season chicken breasts with salt and pepper. Heat olive oil in a skillet over medium-high heat. Cook chicken for 6-7 minutes per side until golden brown, then shred.

In a large pot, bring salted water to a boil. Cook macaroni according to package instructions until al dente, then drain.

In a saucepan, melt butter over medium heat. Stir in flour to create a roux, then gradually whisk in milk. Cook until thickened.

Reduce heat, add cheddar and mozzarella to the sauce, stirring until smooth.

Combine drained macaroni and shredded chicken with cheese sauce, adding BBQ sauce until well coated.

Serve hot with optional additional BBQ sauce and fresh herbs.