Marinate the flank steak in olive oil, chili powder, cumin, garlic powder, salt, and pepper for at least 30 minutes.
Preheat a grill or skillet over medium-high heat.
Cook the marinated steak for about 4-5 minutes on each side.
Remove the steak from the heat and let it rest for 5 minutes.
Warm the corn tortillas on the grill for about 30 seconds on each side.
Slice the steak against the grain into thin strips.
Assemble the tacos by placing steak slices onto each tortilla.
Top with chopped cilantro, diced onions, and a squeeze of lime.
Drizzle with salsa or hot sauce.
Serve immediately and enjoy your delicious steak tacos!