Preheat oven to 400˚F (200˚C).
In a small bowl, mix the chili powder, cumin, cayenne, salt, pepper, and olive oil with the lime juice.
Using a basting brush, generously coat each side of the tilapia fillet with the marinade.
Bake fish for 12 minutes in a preheated oven until edges begin to crisp and fish is moist and flaky.
While fish is baking, prepare the crema.
In a blender, combine avocado, cilantro, salt, pepper, lime juice, and yogurt. Blend until mixture is smooth.
Serve tilapia topped with avocado crema and freshly chopped cilantro.
