Preheat your oven to 400°F (200°C).
Line a large baking sheet with parchment paper or lightly grease.
In a large bowl, combine sliced peppers, onion, olive oil, salt, pepper, chili powder, cumin, and garlic powder. Toss to coat.
Arrange the vegetables evenly on the baking sheet.
Place the flank steak on top of the vegetables.
Drizzle lime juice over the steak and vegetables.
Bake for 20–25 minutes, until the steak reaches your preferred doneness.
Remove from oven and let the steak rest for 5 minutes before slicing thinly against the grain.
Serve with warm tortillas and favorite toppings.