Preheat your oven to 400°F (200°C).

In a large bowl, combine the sliced flank steak, bell peppers, and onion.

Drizzle the olive oil over the mixture and toss to coat evenly.

In a small bowl, mix together the chili powder, cumin, garlic powder, onion powder, paprika, salt, and black pepper.

Sprinkle the spice mixture over the steak and vegetables, tossing again to ensure everything is well coated.

Spread the mixture evenly on a large sheet pan.

Roast in the preheated oven for 20-25 minutes, or until the steak is cooked to your liking and the vegetables are tender.

Remove from the oven and drizzle with lime juice.

Serve immediately with warm tortillas and your choice of toppings.

For a spicier version, add a pinch of cayenne pepper or sliced jalapeños to the spice mix. If you prefer chicken, substitute the flank steak with boneless, skinless chicken breasts or thighs. Vegetarians can replace the meat with portobello mushrooms or extra firm tofu for a hearty alternative. Feel free to experiment with different vegetables like zucchini or cherry tomatoes for added variety. For a smoky flavor, consider adding a teaspoon of smoked paprika.