In a large bowl, drizzle olive oil over chicken breasts, then generously sprinkle Cajun seasoning, garlic powder, onion powder, smoked paprika, salt, and pepper. Coat the chicken evenly.

Heat a skillet over medium heat and add a splash of olive oil. Sear the chicken breasts for 2-3 minutes on each side until golden-brown. Transfer to slow cooker.

Slice the bell pepper and onion into thin strips. Sprinkle over the seared chicken in the slow cooker along with minced garlic.

Add diced tomatoes and chicken broth over the chicken and veggies in the slow cooker.

Cover the slow cooker and cook on low for 4-5 hours, or on high for 2-3 hours.

Remove the chicken from the slow cooker and shred with two forks. Return shredded chicken to the slow cooker.

Pour in the heavy cream and sprinkle Parmesan cheese. Stir gently until fully incorporated.

Cook penne pasta according to package instructions until al dente. Drain and add to the slow cooker, stirring to combine.

Keep the slow cooker on low and heat for an additional 15-20 minutes before serving. Garnish with fresh parsley.