Slice each chicken breast horizontally to create two thinner cutlets. Lightly pound to even thickness for quicker, more even cooking.
In a glass dish, whisk together olive oil, Dijon mustard, honey, lemon juice, minced garlic, Italian seasoning, paprika, salt, and pepper.
Add chicken to the marinade and coat well. Let sit for 15 minutes, or refrigerate up to overnight.
Preheat oven to 400°F.
In a bowl, toss potatoes and onions with olive oil, Italian seasoning, salt, and pepper.
Spread the potato/onion mixture evenly in a large baking dish or oven-safe skillet. Place the raw marinated chicken on top with the marinade. Add in ¼-1/3 cup chicken broth.
Cover tightly with foil and bake for 25 minutes, until potatoes begin to soften.
Remove foil and continue baking for 15–20 minutes, until potatoes are fork-tender and chicken reaches 165°F internal temperature.
Let rest for 5 minutes before slicing and serving.
