Prepare the spice mix: In a medium bowl, combine the chilli and garlic seasoning, Cajun seasoning, and garlic powder.
Season the chicken and prawns: Pat the prawns dry with a paper towel. Toss the prawns and chicken cubes in the spice mix until evenly coated.
Cook the chicken and prawns: Heat the vegetable oil in a cast iron or large frying pan over medium-high heat. Once the oil is shimmering, add the chicken cubes. Fry for about 5-6 minutes until the chicken starts to brown. Add the prawns to the pan and cook for an additional 3-4 minutes, or until both the chicken and prawns are fully cooked.
Prepare the avocado lime cream: In a food processor, blend the avocado, coriander leaves, lime juice, and Greek yogurt until smooth. Season with sea salt and pepper to taste. If the sauce is too thick, gradually add water until you achieve a drizzling consistency.
Make the cabbage slaw: Thinly slice the cabbage into ribbons and place in a large bowl. Add some of the avocado sauce to the cabbage and toss until well coated. Adjust the amount of sauce based on your preference.
Assemble the tacos: Lay the tortillas flat. Add a layer of cabbage slaw, followed by the chicken and prawn mix. Drizzle with additional avocado lime cream.