Combine the pure maple syrup, Dijon mustard, soy sauce, and crushed red pepper flakes in a bowl. Whisk until evenly combined.
Put the wings in a gallon size plastic bag. Add 4-5 tablespoons of the maple dijon sauce. Massage the bag until evenly mixed. Marinate at least 1 hour or overnight in the fridge.
Remove the wings from the bag and season the wings with kosher salt, pepper, and crushed red pepper flakes.
Place the wings on the smoker or Traeger pellet grill set to 250 degrees for 2 1/2 hours, flipping halfway through. Brush the chicken wings with the remaining maple dijon sauce sauce during the last 30 minutes.Use a thermometer to make sure the wings are at 170 degrees.