Begin by preparing the chicken. Cut the boneless, skinless chicken breasts into small, bite-sized pieces.
In a mixing bowl, combine olive oil, chili powder, cumin, garlic powder, salt, and black pepper. Add the chicken pieces to the bowl and toss to coat the chicken evenly with the spice mixture.
Heat the skillet over medium-high heat. Once hot, add the seasoned chicken to the skillet. Cook for 6-8 minutes, stirring frequently, until the chicken is cooked through and no longer pink in the center.
While the chicken is cooking, warm the tortillas in another skillet or microwave until soft and pliable.
Once the chicken is fully cooked, remove the skillet from heat.
To assemble the tacos, place a generous amount of chicken on each tortilla. Top with shredded lettuce, diced tomatoes, shredded cheddar cheese, and chopped cilantro.
Serve with lime wedges on the side for squeezing over the tacos.