Marinate Chicken. In a medium bowl, combine the 2 Tablespoons Greek yogurt, olive oil, chili powder, garlic powder, cumin, lime juice, and salt to make the marinade. Whisk until evenly combined. Add the chicken breasts and flip so that each side is coated. Set aside to rest for 5-10 minutes, or cover and place in the fridge for up to 8 hours.
When ready, grill or sauté the chicken for 3-4 minutes on each side in a skillet lightly coated with olive oil over medium-high heat, until lightly browned and cooked through. Discard the marinade.
While chicken cooks, gently warm tortillas and prepare other toppings as desired. If making the chipotle crema, combine 1/2 cup Greek yogurt and 1-2 tablespoons adobo sauce in a small bowl and stir to combine. Add additional adobo sauce or a squeeze of lime juice to taste.
When chicken is done, remove to a cutting board and slice into bite-sized pieces. Fill tortillas, top as desired, and enjoy!