Preheat the oven to 400°F. Line a baking sheet with parchment paper and spray with nonstick cooking spray.

Thread chicken pieces onto skewers, working the skewer in and out of the meat. Using a pastry brush, brush each piece of chicken with Dijon mustard.

In a food processor, combine the cornflakes, sage, thyme, salt, and pepper. Pulse to a coarse meal and transfer to a shallow dish. Dredge each chicken skewer in the cornflake mixture until evenly coated. Place on prepared baking sheet and bake until cooked through, 8 to 10 minutes. Serve with BBQ sauce.