Nadine's Tangy Fish Tacos Slaw
1 cup creamy salad dressing (such as Miracle … 1 small onion, chopped 1 teaspoon adobo seasoning 2 cups mayonnaise 2 large carrots, shredded 2 spears dill pickle, chopped 2 teaspoons white vinegar 4 teaspoons Cajun seasoning, or more to taste ¼ cup dill pickle juice, or more to taste ½ head red cabbage, finely chopped ½ head white cabbage, finely chopped