Combine the chili powder, cumin, salt, pepper, and oregano in a small bowl. Divide in half and set aside
Place the chicken tenders in a bowl and sprinkle half the seasoning mixture plus a drizzle of neutral oil. Toss to coat evenly and set aside
Heat a large sauté pan over medium-high heat. Add the oil and heat through. Add the carrots, onions, bell peppers, jalapenos (if using) and cook until they just begin to soften, about 2 minutes
Add the mushrooms, sauté for about 1 minute, then add the garlic and the other half of the seasoning mix. Stir constantly, until vegetables are tender-crisp.
Remove from the pan and place in a serving bowl. Sprinkle the cilantro over all.
In the same pan over medium-high heat, add the seasoned chicken tenders and cook until internal temperature reaches 160℉. Remove from the pan into a serving bowl.
Spoon the fajita filling onto a warm tortilla. Squeeze a wedge of lime over the filling and top with Pico de Gallo, sour cream and diced avocados