Whisk together the 3 tbsp Dijon mustard, 3 tbsp honey, 2 tbsp mayonnaise, and 1 tsp lemon juice. Reserve 3 tbsp for finishing, then season the chicken with the garlic powder, onion powder, smoked paprika, salt, and pepper and coat in the remaining marinade. Refrigerate for at least 30 minutes.

Cook the 8 bacon strips in a large oven-safe skillet over medium heat for 8 to 10 minutes until crispy. Remove and drain, keeping about 1 tsp drippings in the pan. Break each strip in half.

Sear the marinated chicken over medium-high heat for 5 to 6 minutes per side until deeply golden, reaching at least 150°F (66°C) internally. Remove to a plate.

Add the 1 tbsp olive oil to the skillet, then cook the 8 oz sliced mushrooms over medium-high heat without stirring for 3 minutes, then toss and cook another 2 to 3 minutes until browned.

Set the broiler to high. Return the chicken to the skillet, spoon the reserved 3 tbsp sauce over each breast, top with mushrooms, bacon, and the 1 cup Colby-Jack cheese. Broil on the top rack for 3 to 4 minutes until the cheese is bubbling and the chicken hits 165°F (74°C).

Transfer to warm plates and garnish with the 1 tbsp chopped parsley. Serve immediately.