Preheat a large skillet or pan over medium heat and add a light drizzle of olive oil.
Add the chopped onion to the pan and sauté for 2-3 minutes until softened.
Add the ground turkey and cook, breaking it into small pieces, until no longer pink, about 5-7 minutes.
Stir in the diced bell pepper and cook for 2 more minutes.
Add the diced tomatoes, chili powder, garlic powder, onion powder, and taco seasoning. Stir to combine and let simmer for 5 minutes.
Squeeze in the lime juice and stir to brighten the flavors.
Turn off the heat and let the mixture cool slightly.
Using iceberg or romaine lettuce, create ‘boats’ by placing a cupped lettuce leaf on a plate and filling it with the turkey mixture.
Top each serving with fresh cilantro, avocado slices, and extra lime juice if desired.