Preheat the oven to 450 degrees F (230 degrees C). Spray a large 11x17-inch sheet pan with cooking spray.
Combine olive oil, paprika, oregano, and salt in a large bowl. Add chicken, potatoes, and onion and toss to coat. Arrange in a single layer on the prepared pan.
Roast in the preheated oven for 25 minutes.
Remove pan from oven and stir vegetables gently. Nestle sausage pieces among chicken and vegetables. Return pan to the hot oven and roast until potatoes are tender and chicken is no longer pink in the center, 10 to 15 minutes more. An instant-read thermometer inserted into the center of a thigh should read at least 165 degrees F (74 degrees C).
Remove pan from oven and sprinkle chicken and vegetables with orange zest and juice. Toss gently and serve.