Heat olive oil in a skillet over medium-high heat.

Add onion, cook until translucent.

Toss in the chopped brisket and sprinkle chili powder, cumin, salt, and pepper.

Stir until the edges turn crisp and the brisket absorbs the spices.

Warm tortillas on a dry skillet or directly over the flame for that light char.

Fill each tortilla with brisket, top with cilantro, tomatoes, and avocado.