Add vegetable oil to a skillet and turn to medium-high. Add peppers and stir fry for about 4 minutes. Add onions and cook until vegetables are cooked as desired. Remove pepper mixture from pan, place in a large bowl and cover to keep warm.
Add steak to the pan and cook for about 7 minutes or until cooked as you like.
Add cooked steak to pepper mixture. Add in chili powder, salt, lime juice, olive oil, and fresh garlic. Toss well to coat.
Heat tortillas according to package directions. Spoon steak/vegetable mixture evenly over tortillas and top with chopped cilantro and sour cream.