Preheat the oven to 400°F. Line a baking sheet with parchment paper.
In a small bowl, mix together the chili powder, cumin, garlic powder, paprika, salt, and pepper. Rub the spice mixture over the salmon fillets.
Place the salmon on the prepared baking sheet and drizzle with olive oil. Bake for 12-15 minutes, or until the salmon flakes easily with a fork.
While the salmon is baking, prepare the avocado lime sauce. In a blender or food processor, combine the avocado, sour cream, lime juice, garlic powder, and salt. Blend until smooth. If the sauce is too thick, add a little water to reach your desired consistency.
Once the salmon is cooked, remove it from the oven and let it cool slightly. Flake the salmon into bite-sized pieces with a fork.
Warm the corn tortillas in a dry skillet over medium heat for about 30 seconds on each side, or until pliable.
To assemble the tacos, place a portion of flaked salmon on each tortilla. Top with shredded cabbage, diced tomatoes, and fresh cilantro. Drizzle with avocado lime sauce.
Serve immediately.