In a bowl mix chicken with 1 tablespoon olive oil and Cajun seasoning, stirring thoroughly to coat.
Heat 1 tablespoon olive oil in a pan over medium high heat. Add chicken and cook, flipping once, until cooked through, about 5-6 minutes on each side. Set aside and keep warm.
In a large pot of boiling salted water, cook pasta according to package instructions and drain.
Melt butter in a saucepan over medium heat. Add garlic and sauté until fragrant, about 1-2 minutes. Add diced tomatoes.
Gradually whisk in heavy cream. Cook, whisking constantly, until incorporated, about 1-2 minutes. Stir in Parmesan until slightly thickened, about 1-2 minutes. If the mixture is too thick, add more heavy cream as needed; season with salt and pepper, to taste.
Stir in pasta and gently toss to combine.
Serve immediately with chicken, garnished with tomatoes and parsley