Rinse the chicken and pat dry with paper towels. Remove the chicken breasts from the bone and discard the skin. Cut each breast into 10 strips.
Whisk the egg and 2 tablespoons water in a bowl and set aside. Mix the flour, poultry seasoning and salt and pepper, to taste, in a resealable plastic bag. Add the chicken strips and toss to coat, set aside. Put the bread crumbs in a shallow dish or pie plate. Remove the chicken from the bag and shake off the excess flour. Coat the chicken in the egg, than dredge in the panko bread crumbs. Arrange the strips in a single layer, on a baking sheet, allowing space in between each strip.
Bake for 15 to 20 minutes, until chicken is golden brown and cooked through.
For the Sweet Mustard sauce:
In a small bowl, combine the mustard, mayonnaise and the brown sugar. Mix until sugar dissolves completely.
Warm the tortillas in a microwave for 30 seconds to make them pliable. Lay a tortilla flat onto a work surface. Place about 5 chicken strips onto the tortilla. Drizzle with the sweet mustard sauce and top with cheese, lettuce and pickle. Roll up the tortilla and put on a serving platter. Repeat with remaining ingredients and serve.