Bring a large saucepan of lightly salted water to a boil; cook the pasta about 8-10 minutes or until tender yet firm to the bite. Drain.
Meanwhile, heat the olive oil in a large deep frying pan on medium-high heat. Cook the chicken, onion powder, garlic, salt and black pepper, stirring, for 5-7 minutes or until chicken is just cooked through. Reduce heat to low.
Whisk chicken stock and flour together in a bowl until well blended. Pour over the chicken in the frying pan. Add half the Cheddar cheese, diced tomatoes, cream, butter, hot sauce and Worcestershire sauce; stir to combine. Continue stirring over medium heat about 10 minutes or until sauce starts to thicken. Add the cooked pasta and toss to combine.
Pour chicken-pasta mixture into a 3-litre (12-cup) ceramic baking dish. Sprinkle remaining Cheddar cheese on top. Bake in the oven about 15 minutes or until cheese is bubbly and melted.
Top with breadcrumbs right before baking if desired.