Rub tilapia fillets with 2 tablespoons lime juice and season with salt, black pepper, garlic powder, and paprika. Spray both sides of each fillet with cooking spray.
Preheat grill for medium heat and lightly oil the grate.
Combine yogurt, 2 tablespoons lime juice, cilantro, and chipotle pepper in a blender; pulse until sauce is well blended. Set aside.
Grill tilapia on preheated grill until fish is easily flaked with a fork, about 5 minutes on each side.
Heat each corn tortilla in a skillet over medium-low heat until warm, about 1 minute. Divide grilled fish evenly over corn tortillas and serve with cilantro-lime sauce, cabbage, Monterey Jack cheese, tomato, avocado, salsa, and green onions.