Heat 1 tablespoon olive oil in a nonstick skillet over medium heat.
Add 1 clove garlic and cook 30 seconds.
Add the zucchini, cover and cook until tender, stirring, about 6 minutes.
Transfer to a bowl.
Heat another tablespoon oil in the skillet over medium-high heat. Season the chicken with 1/4 teaspoon each salt and pepper and cook through, 2 to 3 minutes per side.
Transfer to a plate. Cook the pasta in the boiling water as the label directs.
Drain, reserving 1/2 cup cooking water; return the pasta to the pot. Meanwhile, whisk the flour and low-fat milk in a bowl.
Place the remaining 1 clove garlic and 1 tablespoon oil in the skillet and cook over medium-high heat, 30 seconds.
Add the flour-milk mixture and bring to a boil, stirring. Reduce the heat to low and cook, stirring, 2 minutes.
Add the evaporated milk, 1/2 teaspoon salt and the cheese; stir to melt, 1 minute.
Cut the chicken into strips. Toss with the pasta, sauce, zucchini and parsley, adding the reserved pasta water to loosen.