Preheat the oven to 400°F (200°C). Lightly grease a 9x13-inch casserole dish.
Prepare the potatoes. In a large bowl, combine cubed potatoes, olive oil, garlic powder, onion powder, paprika, salt, and pepper. Toss until evenly coated.
Bake the potatoes. Spread the seasoned potatoes on a baking sheet and roast for 20 minutes until lightly golden but not fully cooked.
Season the chicken. In the same bowl, toss cubed chicken with a drizzle of olive oil, salt, and pepper. This step layers flavor into the protein before baking.
Assemble the casserole. Transfer the partially roasted potatoes into the casserole dish. Add chicken, broccoli florets, carrots, bell peppers, and peas. Mix lightly to distribute.
Add cream and cheese. Pour heavy cream evenly over the mixture. Sprinkle shredded cheddar cheese on top.
Bake again. Return to the oven and bake for 25–30 minutes, or until the chicken is fully cooked, vegetables are tender, and the cheese is bubbling and golden.
Serve hot. Let cool for 5 minutes, then scoop generous portions onto plates.
