Spinach Chicken Alfredo

boneless, skinless chicken breasts

frozen spinach, thawed and drained

seasoned diced tomatoes (with basil and oregano)

garlic, minced

yellow onion, chopped

milk

parmesan cheese, grated

heavy cream

low-sodium chicken stock

cornstarch

dried basil

dried oregano

olive oil, as needed

kosher salt and freshly ground pepper,