Preheat the oven to 425 degrees F.
Place the onions and peppers on a baking sheet. Toss with 2 tablespoons of the olive oil and a big pinch of salt and pepper, along with the garlic powder. Toss well.
Place the rounds of smoked sausage on top of the peppers and onions, kind of nestled into the sheet pan.
Roast for 15 to 20 minutes.
While the sausage and vegetables roast, bring a pot of salted water to a boil. Cook the cheese tortellini according to the directions, shaving 1 minute off the cook time. Drain once it’s finished.
Remove the pan from the oven. Add the tortellini to the sheet pan and toss well with the remaining 2 tablespoons of olive oil. Sprinkle on the parmesan cheese.
Return the pan to the oven for 10 to 15 more minutes, tossing once or twice during cook time.
Remove the pan. Serve immediately with a sprinkling of chives and more parmesan.