Heat 2 tablespoons oil in a large skillet over medium-high heat. Add onion, and cook, stirring often, until translucent, 5 to 7 minutes. Add turkey; cook, stirring often, until starting to brown, 5 to 7 minutes.
Add zucchini, bell pepper, and 1 cup salsa; cook until vegetables are crisp-tender, 5 to 6 minutes. Season with salt and ground pepper. Transfer to a plate, and let cool.
In a large bowl, toss lettuce with tortilla chips, tomatoes, and remaining 1/2 cup salsa and 2 tablespoons oil. Transfer to serving plates, and top with turkey mixture and cheese.