Cook your chicken and shred it into bite-sized pieces.
Cook the rotini pasta according to package instructions until al dente, then drain.
In a large pot, heat olive oil over medium heat. Sauté diced onion until translucent, about 5 minutes, then add minced garlic and cook for 1 minute.
Add shredded chicken to the pot, pour in chicken broth, and bring to a gentle simmer. Then add milk, cooked rotini pasta, Dijon mustard, and paprika. Cook for 5 minutes.
Gradually add shredded cheddar cheese, stirring continuously until melted. Season with salt and pepper to taste, and serve hot garnished with chopped parsley.