Heat the olive oil in a large pot over medium heat.
Season the diced chicken with Cajun seasoning, salt, pepper, and paprika.
Cook the chicken until golden brown and fully cooked, about 6–8 minutes. Remove from the pot and set aside.
Melt the butter in the same pot.
Add the minced garlic and sauté for about 1 minute until fragrant.
Stir in the orzo and toast for 1–2 minutes.
Pour in the chicken broth and bring to a gentle simmer.
Cook, stirring occasionally, until the orzo is tender and most of the broth has been absorbed.
Reduce the heat and stir in the heavy cream and Parmesan cheese until smooth and creamy.
Return the chicken to the pot and stir well. Add spinach or bell peppers if desired.
Simmer for another 2–3 minutes until everything is heated through.
Garnish with fresh parsley and serve your One Pot Cajun Chicken Alfredo Orzo warm.