Heat the oil in a medium skillet over medium-high heat. Add the onion and cook, stirring, until slightly soft, about 4 minutes.
Add the turkey and cook, crumbling with the back of a wooden spoon, until no trace of pink remains, 5 to 7 minutes.
Stir in the chili powder and ½ teaspoon salt.
Divide the turkey mixture, tortilla chips, lettuce, Cheddar, and avocado among individual plates. Serve with the salsa.