Bring a large pot of salted water to a boil. Add penne pasta and cook according to package instructions until al dente. Drain and set aside.
While the pasta cooks, heat olive oil in a large skillet over medium-high heat.
Toss chicken pieces with Cajun seasoning until evenly coated.
Add the seasoned chicken to the skillet and cook for 5-7 minutes, stirring occasionally, until browned and cooked through. Remove chicken from skillet and set aside.
In the same skillet, add sliced red bell pepper, green bell pepper, and yellow onion. Sauté for 4-5 minutes until vegetables are tender-crisp.
Add minced garlic and smoked paprika to the vegetables and cook for 1 minute until fragrant.
Pour in chicken broth and bring to a simmer. Let it reduce slightly for 3 minutes.
Reduce heat to medium-low and stir in heavy cream, shredded cheddar cheese, and hot sauce. Stir continuously until cheese is melted and sauce is creamy.
Return cooked chicken to the skillet and add the drained pasta. Toss everything together to coat evenly with the sauce.
Season with salt and freshly ground black pepper to taste.
Cook for an additional 2-3 minutes, stirring occasionally, until heated through.
Remove from heat and garnish with chopped green onions before serving.