In a large pan heat 1 tbsp oil over medium-high heat. Sprinkle chicken with enough Cajun seasoning to coat lightly. Place half the chicken in the pan (making sure not to crowd the chicken), let the chicken brown on one side for 2-3 minutes then flip over and finish browning on the other side for 2-3 minutes. Remove chicken with a slotted spoon to a clean plate. Repeat with remaining chicken.
Turn heat up to high and add the remaining tbsp of oil. Toss in the onion, red bell pepper and garlic. Sprinkle with a little more Cajun seasoning and salt and pepper. Try not to stir the mixture too much, let it caramelize and blacken slightly. After about 4-5 minutes add the mushrooms and cook for an additional 2-3 minutes. Remove the veggies to the plate with the chicken.
Back in the pan add 1/2 cup white cooking wine, chicken stock concentrate and water (or substitute the concentrate and water for 1 1/2 cups chicken broth). Bring to a boil and scrap any browned bits off the bottom of the pan. Let the mixture cook for a bit and reduce in size by half.
Turn the heat down to medium and add the heavy cream and cream cheese. Stir with a whisk until mixture is smooth and creamy.
Add the chicken and veggies back to the pan and stir to coat, cooking until mixture thickens (about 2-3 minutes). Add in the cooked pasta and toss to coat.
Serve topped with the diced tomatoes and sliced green onions and a little Parmesan cheese on top.