Cook the pasta al dente, according to package directions. Drain and place back into the the pot.
In a medium saucepan, heat the olive oil over medium heat. Add the garlic, stirring frequently, until golden, 1 to 2 minutes.
Whisk in the flour until smooth, about 2 minutes. Gradually whisk in the chicken broth, milk, salt, pepper and smoked paprika. Bring to a low boil, stirring constantly. Lower the heat and simmer, stirring gently, until the mixture thickens for another 3 minutes. Add 1 cup Parmesan cheese; mix well.
Pour the sauce over the pasta and toss; add the chicken and mix well. Spread the pasta mixture in a prepared (greased) baking pan, and top with ½ cup more Parmesan cheese.
Bake for 20-25 minutes, until the cheese is melted and just barely starts to turn golden. Garnish with green onions or chopped fresh basil; serve.