Heat the oven to 425℉. Line a large, rimmed baking sheet with parchment paper or grease lightly with oil spray.
Make the marinade: In a bowl or liquid measuring cup, mix the lemon zest, lemon juice, mustard, honey, olive oil, salt, pepper, garlic powder, onion, powder, and dried dill.
Add the radishes, potatoes, and carrots to a large bowl. Drizzle with 2 tablespoons of the marinade and toss to coat. Dump onto the prepared sheet pan and spread into an even layer.
Place the chicken in the same bowl and pour the remaining marinade over the top. Use tongs or a large spoon to mix and coat the chicken in the marinade.
Make some room for the chicken on the sheet pan in and around the vegetables (It’s ok if ingredients touch but try to not let them overlap too much.) Spoon any remaining marinade left in the bowl over the chicken then sprinkle the remaining ½ teaspoon of salt over the whole sheet pan.
Place the pan in the oven and roast until the vegetables are tender and the chicken has an internal temperature of 165℉, about 30 to 35 minutes. If you’d like the top of the chicken to be more browned, place the pan under the broiler for a few minutes.
Sprinkle the cooked chicken and vegetables with chopped fresh herbs and serve with lemon wedges to squeeze over the top.