Heat 1 tablespoon of olive oil in a large skillet over medium-high heat.
Add the sliced chicken and season with chili powder, cumin, garlic powder, salt, and pepper. Cook for about 5-7 minutes, or until the chicken is cooked through and no longer pink. Remove the chicken from the skillet and set aside.
In the same skillet, add the remaining tablespoon of olive oil. Add the sliced bell peppers and onion. Sauté for about 5-6 minutes, or until the vegetables are tender and slightly charred.
While the vegetables are cooking, prepare the creamy jalapeño verde sauce. In a blender or food processor, combine Greek yogurt, cilantro, jalapeños, lime juice, and salt. Blend until smooth and creamy.
Return the cooked chicken to the skillet with the sautéed vegetables. Toss everything together and heat for an additional 2 minutes to combine flavors.
Warm the flour tortillas in a dry skillet or microwave. Serve the chicken and vegetable mixture in the tortillas, drizzled with the creamy jalapeño verde sauce.