In a bowl, mix the crushed cornflakes and bbq seasoning. Dip each chicken breast into the beaten egg, ensuring even coverage, then press into the cornflake mixture, ensuring they're well-coated.
Add the chicken breasts to an air fryer and cook until golden brown.
In a small bowl, mix together the bbq sauce and honey.
Slice open the brioche buns. On the bottom half, place a layer of lettuce, followed by the cheesy chicken breast and a few halved cherry tomatoes. Top with the other half of the brioche bun.