Fill a large pot with water, add a pinch of salt, and bring to a rolling boil. Add pasta and cook 8–10 minutes until tender but still slightly firm (al dente). Drain and reserve 1 cup pasta water. Set pasta aside.

Heat oil in a large pot or Dutch oven over medium-high heat. Add smoked sausage and brown on all sides (about 5 minutes). Remove and set aside.

In the same pot, add chicken pieces, season with 1 tbsp Cajun seasoning, and brown until cooked through (about 8 minutes). Remove and set aside with the sausage.

Add the beef to the pot, season with additional Cajun seasoning, and brown on all sides (6–8 minutes). If beef seems tough, add a splash of chicken broth, cover, and simmer 10–15 minutes until tender.

Add diced onion, bell pepper, and celery to the pot with the beef. Cook 7–8 minutes, stirring occasionally, until softened. Add minced garlic in the last minute and sauté briefly.

Pour in the Rotel tomatoes with their juices, then add heavy cream and chicken broth. Stir to combine and bring to a gentle simmer.

Reduce heat to low and add cubed Velveeta and cream cheese. Stir constantly until the cheeses melt into a smooth, creamy sauce (about 5 minutes). Be patient and keep heat low to avoid separation.

Return the sausage and chicken to the pot, gently stirring to coat. Add the cooked pasta and fold carefully so the pasta holds its shape. Simmer together ~5 minutes so the pasta absorbs sauce. If sauce is too thick, loosen with reserved pasta water or extra broth.

Taste and add more Cajun seasoning, salt, or pepper as needed. Serve hot, garnished with chopped green onions or parsley if desired. The cheese will thicken as it cools, so serve promptly.