Prepare pasta; drain, reserving 1 cup of pasta water. Set both aside.
Heat olive oil in a Dutch oven over medium heat.
Add chicken; sprinkle with 2 teaspoons Cajun seasoning. Cook, stirring occasionally, until cooked through, 5 to 7 minutes. Remove from pan, and set aside.
Add sausage, onion, bell pepper, celery, and 1 teaspoon Cajun seasoning to pan. Cook, stirring occasionally, until vegetables are softened, about 5 minutes.
Add garlic to pan; cook, stirring constantly, 2 minutes. Add wine; stir to release browned bits from bottom of pan.
Add cream to pan; stir to combine. Return chicken to pan; stir in cooked pasta.
Stir in yogurt; add reserved pasta water, ¼ cup at a time, until pasta reaches desired consistency.
Taste and season with remaining 1 teaspoon Cajun seasoning and additional salt, if desired.
Garnish servings with green onion and a sprinkle of Cajun seasoning, if desired.