Preheat oven to 425°F (218°C). Line a large sheet pan with parchment or foil for easier cleanup.
Chop chicken and veggies into bite-sized pieces. Toss everything in a large bowl.
Add olive oil, seasonings, and toss until coated.
Spread evenly onto the sheet pan in a single layer.
Bake for 20-25 minutes, flipping halfway through, until chicken is cooked through (165°F) and veggies are golden and tender.
Sprinkle cheese, if using, during the last 5 minutes or just after removing from oven.
Serve hot over a carb of your choice or just as-is for a lower-carb plate.