Combine the ingredients for the Cajun seasoning in a small bowl. Cut the chicken into 1/2 to 3/4-inch cubes. Place the cubed chicken in a bowl, pour the Cajun seasoning over top, and stir to coat the chicken in spices.
Add the olive oil and butter to a wide pot with a lid. Heat the oil and butter over medium-high until the butter is melted and foamy. Add the seasoned chicken to the skillet and cook for a couple minutes on each side, or just until the outside gets some color. The chicken does not need to be cooked through at this point.
Add the scallions and continue to sauté for a minute more. Add the tomatoes and their juices, stirring to scrape any browned bits from the bottom of the pot.
Next, add the pasta and chicken broth. Stir just until everything is evenly combined, then place a lid on top and allow the broth to come up to a boil. Once boiling, turn the heat down to medium-low and let the pasta simmer for about ten minutes, stirring every few minutes, until the pasta is tender.
When the pasta is ready, turn the heat very low and add the cubed cream cheese, stirring as it melts into the sauce. Remove from the heat. Serves 4 generously.