Cook the fettuccine according to package instructions; drain and set aside.

In a large skillet, heat 1 Tbsp olive oil and 1 Tbsp butter over medium-high heat.

Add the chicken pieces and season with 1/2 Tbsp Cajun seasoning, cooking until browned and cooked through.

Remove the chicken and set aside.

In the same skillet, add the remaining olive oil and butter, then add the bell peppers, red onion, garlic, and season with salt and black pepper; sauté until tender.

Stir in the remaining Cajun seasoning, diced tomatoes, white wine, chicken broth, and heavy cream; bring to a simmer.

Return the cooked chicken to the skillet and mix well, cooking until heated through.

Serve the chicken mixture over the cooked fettuccine.