In a large bowl, whisk together Dijon mustard, vinegar, honey, garlic powder, paprika, crushed red pepper, salt, and pepper. Add chicken and toss to coat. Let marinate for at least 15 minutes while the oven preheats.
2 lbs boneless skinless chicken breast, 2 tbsp Dijon mustard, 2 tbsp apple cider vinegar, 1 tsp honey, 1 tsp garlic powder, 1/2 tsp smoked paprika, 1/4 tsp crushed red pepper flakes, 1/2 tsp salt, 1/4 tsp black pepper