Adjust rack to middle position (middle and top positions for 4 servings) and preheat oven to 425 degrees. Wash and dry produce.

Dice potatoes into ½-inch pieces. Trim, peel, and cut carrots on a diagonal into ½-inch-thick pieces.

In a small bowl, combine panko, mozzarella, half the mayonnaise, a pinch of salt, and pepper. 

Toss potatoes and carrots on one side of a baking sheet with a drizzle of oil, salt, and pepper; arrange in a single layer (for 4, spread out across entire sheet).

Pat chicken* dry with paper towels and season all over with salt and pepper.

Add chicken to opposite side of baking sheet from veggies (for 4 servings, place chicken on a second baking sheet). Spread tops of chicken with remaining mayonnaise; top with panko mixture, pressing to adhere (no need to coat the undersides).

Roast on middle rack until veggies are tender, panko is golden brown, and chicken is cooked through, 20-25 minutes. (For 4, roast on middle and top racks, swapping rack positions halfway through.) TIP: If chicken is done before veggies, carefully transfer to a plate and continue to roast veggies. 

Meanwhile, dice tomato into ¼-inch pieces. Finely chop parsley. Peel and mince garlic. Zest and quarter lemon. 

In second small bowl, combine tomato, parsley, garlic, juice from half the lemon, a pinch of salt, pepper, and as much lemon zest as you like. 

Divide chicken and veggie jumble between plates. Spoon tomato topping over chicken. Serve with remaining lemon wedges on the side.