Preheat your oven to 400 degrees Fahrenheit and line a large baking sheet with parchment paper for easy cleanup.
Slice the chicken sausage into half-inch rounds and thinly slice the bell peppers and red onion into strips.
Place the sausage, peppers, and onions onto the prepared baking sheet.
Drizzle with olive oil and sprinkle with sea salt, black pepper, dried oregano, and garlic powder.
Toss everything together with your hands or tongs until the ingredients are evenly coated in oil and spices.
Spread the mixture into a single layer, ensuring the pieces aren't too crowded so they roast rather than steam.
Roast in the oven for 20 to 25 minutes, tossing halfway through, until the sausage is browned and the vegetables are tender and slightly charred.
Remove from the oven and immediately sprinkle with nutritional yeast while still hot to add a savory, cheesy flavor.