In a large bowl, combine the mayonnaise, vinegar, Creole mustard, and seasoning.
To the dressing, add the coleslaw mix, onions, and carrots. Toss to coat the slaw with the dressing and refrigerate until ready to serve.
Notes
Be sure to add dressing slowly because cabbage size and salad mix bag size will vary. For this reason, I suggest you double your dressing batch and keep extras in the fridge.