1. Preheat the oven to 200°C (400°F).

2. In a bowl, mix together mayonnaise, brown sugar, mustard, paprika, salt, and pepper.

3. Brush the chicken breast with the mayonnaise mixture and place it in a baking dish.

4. Place the baking dish in the preheated oven and bake for 25-30 minutes until the chicken is cooked through.

5. While the chicken is in the oven, peel and boil the potatoes until they are tender.

6. Drain the cooked potatoes and roughly mash them. Season with salt and pepper.

7. Serve the oven-baked honey mustard chicken with the mashed potatoes and enjoy!