Preheat oven to 350 degrees F. Spray a 9- x 13-inch baking dish with cooking spray and set aside.
2
Melt butter in a large skillet over medium-high heat. Add flour and stir to cook for about 1 minute. Whisk in broth, milk, salt and thyme and bring to a simmer, stirring constantly. Allow sauce to cook until it thickens, whisking regularly so that the sauce is smooth (about 5-10 minutes).
3
Remove from heat, stir in cooked pasta, ½ cup of mozzarella, chicken, zucchini, and corn.
4
Transfer chicken mixture to prepared dish. Top with remaining mozzarella and sprinkle with Parmesan.
5
Bake, uncovered, until bubbly and heated through (about 20-25 minutes).