Heat the oil in a large saucepan over medium-high heat, add the chicken, seasoned with the Cajun seasoning, and cook until golden brown, about 2-4 minutes per side, before setting aside.
Melt the butter in the same saucepan before adding the onion, celery and bell pepper and cooking until tender, about 5-7 minutes.
Add the garlic, thyme, and Cajun seasoning, and cook until fragrant, about a minute.
Add the broth, chicken, diced tomatoes, Worcestershire sauce, and pasta, bring to a boil, reduce the heat and simmer until the pasta is al-dente tender, about 7 minutes.
Remove the chicken, slice or shred it, and return it to the pot.
Turn off the heat, add the cream and parmesan, mix and let the cheese melt into the broth.
Add the lemon juice, parsley and green onions, and season with cayenne, salt and pepper to taste before enjoying!
Slow Cooker: Optionally implement steps 1-3, place everything up to (not including) the pasta into the slow cooker and cook on LOW for 6-10 hours or HIGH for 2-4 hours, before adding the pasta and cooking on HIGH until tender, about 10 minutes, and continue with steps 5-7.
Option: Add 1 teaspoon old bay seasoning.
Option: Add 4 ounces cream cheese, warmed, along with the parmesan.
Option: Add 8 ounces andouille sausage, sliced or diced and browned.
Option: Add 4 slices bacon, cooked and crumbled.