Preheat the oven to 425 degrees F.
Put the apple cider vinegar, sugar, and 1/4 teaspoon salt in a large bowl with a cover (large enough to fit all of the cabbage). Swirl the vinegar mixture around till combined.
Add the cabbage or coleslaw mix to the bowl. Cover and flip the bowl over to let the vinegar mixture mix in with the cabbage. Flip the bowl a couple more times between other steps.
Arrange the tilapia on a nonstick baking sheet. Bake for 13 to 15 minutes if baking from frozen, 9 to 11 if the tilapia is already thawed.
While the tilapia is cooking, slice the mango and avocado into thin strips. Set aside.
In a small bowl mix together the sour cream, lime juice, and remaining 1/4 teaspoon salt to make the lime crema. Set aside.
When the fish is done baking, use a large spatula to move all the fish to a medium bowl. Add the taco seasoning and use the spatula to combine the fish with the seasoning, breaking up the tilapia into small pieces in the process.
Serve the tacos with the cabbage slaw, taco flavored tilapia, mango, and avocado. Spoon the lime crema on top and serve with cilantro.