Chicken Pesto Mac and Cheese

Name: Chicken Pesto Mac and Cheese
Prep time: 5 min
Cook time: 25 min
Total time: 30 min
Cuisine: American
Ingredients: 1 tablespoon olive oil; 1 boneless chicken breast cut in bite size pieces; 1/4 cup butter; 3 tablespoons flour; 2 cups milk (full fat); 1 1/4 cups water; 1 1/4 cups chicken stock; 2 cups uncooked elbow macaroni; 1 cup mozzarella cheese (shredded); 2 cups sharp cheddar cheese (shredded); salt and pepper to taste; 1/2 teaspoon dry mustard; 1/2 cup pesto (homemade or store-bought + OPTIONAL extra pesto for garnish/serving)