Slice the chicken or beef into thin strips and combine with lime juice, olive oil, chili powder, cumin, paprika, garlic powder, onion powder, salt, and black pepper in a bowl. Mix well to ensure the meat is fully coated, then cover and refrigerate for at least 30 minutes, or up to 2 hours for enhanced flavor.

Slice the bell peppers and onion into thin strips. In a large skillet or cast-iron pan, heat 1 tablespoon of olive oil over medium-high heat. Add the sliced vegetables to the pan, season with salt and pepper, and sauté for 5-7 minutes until they are tender-crisp and slightly charred.

Remove the vegetables from the skillet and set them aside. Add the marinated meat to the same hot skillet, ensuring not to overcrowd the pan; cook in batches if necessary. Cook the meat for 3-5 minutes per side, or until it is fully cooked through and has a nice char.

Once the meat is cooked, return the sautéed vegetables to the skillet and toss everything together to combine. Warm the flour tortillas according to package directions. Serve the fajita mixture in the warm tortillas with your favorite toppings such as salsa, sour cream, guacamole, and shredded cheese.