Carefully remove the kernels from the corn cob and place in a bowl. Cube the avocado and add to the bowl with sweet corn. Squeeze in the lime juice followed by the salt and cilantro. Toss until the corn and avocado are coated, set aside.
Heat the blacks beans, vegetable stock, cumin, coriander, and garlic powder on a low simmer.
Heat the tortillas as desired. Assemble the tacos with a a few spoonfuls of the black beans followed by the avocado relish, cotija cheese, and a drizzle of hot sauce.