Cut the chicken breast into bite-sized pieces and season with salt and pepper.
Heat olive oil in a pan and grill the chicken breast until golden brown.
Thinly slice the cabbage and carrot, and place them in a bowl along with chopped onion.
Add mayonnaise, vinegar, sugar, salt, and pepper, then mix to make coleslaw.
Slice ciabatta or regular sandwich bread in half and toast them.
Layer the grilled chicken breast and coleslaw on the bread in order.
Top with hot sauce if desired to finish the sandwich.