Preheat oven to 400°F and line a baking sheet with parchment paper.
Dice the potato into small 0.5-inch cubes and toss with olive oil, half the salt, pepper, and garlic powder.
Spread potatoes on the baking sheet and roast for 20-25 minutes until golden and crispy.
Season the chicken breast with the remaining salt, pepper, and garlic powder, then pan-sear until cooked through to 165°F.
Slice the cooked chicken into thin strips.
In a small bowl, whisk together the Greek yogurt and lemon juice to create a zesty dressing.
Warm the tortilla slightly, then layer with fresh spinach, roasted potatoes, and sliced chicken.
Drizzle with the yogurt sauce, fold in the sides, and roll tightly to serve.