Preheat the oven to 400 degrees. Combine the broccoli slaw, mayonnaise, sugar, ½ of the lime juice, hot sauce, and mirin together in a bowl with salt and pepper.
Season the fish with salt and pepper and put on a sheet tray. Cook in the oven for 5-10 minutes depending on thickness. Assemble the tacos on tortillas with cod, sliced jalapeno, slaw, sliced avocado, cilantro, sriracha, and a squeeze of the remaining lime juice.