Preheat your oven to 425 degrees Fahrenheit and prepare a large baking sheet by spraying it with cooking spray (and/or line it with parchment paper for even easier clean up!)
Make sure all the veggies are cut into pieces that are the appropriate size so they cook evenly. The potatoes should be cut into 1 or 1 1/2-inch pieces because they take longer to cook, the zucchini, broccoli, and cauliflower into 3-4-inch pieces because they cook faster.
Add the broccoli, cauliflower, onion, tomatoes, zucchini, frozen carrots (use frozen...fresh will take a lot longer to roast!), and potatoes to the baking sheet.
Drizzle the veggies with the olive oil, parsley, oregano, salt and pepper.
Toss the veggies well in the oil and spices and arrange them in an even layer.
Add the chicken sausages on top of the veggies, and roast at 425 degrees Fahrenheit for about 20-25 minutes, or until the potatoes are fork tender and the sausages are cooked through to an internal temperature of 165 Fahrenheit (74 Celsius).