Combine creamy sauce ingredients in a small bowl. Mix and set aside. Combine mango salsa ingredients in a medium bowl. Stir to mix and set aside. Both can be made in advance and kept in the fridge.
Whisk flour, garlic powder, paprika, and a pinch of salt to a medium bowl. Whisk in the beer until smooth. Let the batter rest for 10 minutes while prepping the fish. The foam should subside entirely.
In a Dutch oven or saucepan, bring oil to 365°F. Frying works best if the fish is completely submerged in oil.
Cut the cod filet into small taco portions, pat dry with a paper towel, and season with salt. Dredge in a light coating of flour.
Submerge fish in the beer batter. Remove, let excess drip off, and immediately transfer to the hot oil. Deep fry each piece for 4-5 minutes. Remove fish with a slotted spoon or spider strainer and place on a sheet to rest for 5 minutes before serving.
Serve tacos with toasted tortillas, lime wedges, mango salsa and a drizzle of creamy chipotle sauce.