1. Heat oil in a large nonstick skillet over medium heat. Add shrimp, cumin, and garlic; sauté 3 minutes or until shrimp are pink.
2. Combine cooked shrimp, crab, sour cream, and green onions in a large bowl.
3. Spread tortilla chips on an aluminum foil-lined baking sheet. Top with shrimp mixture. Sprinkle with cheese, and top with jalapeño.
4. Broil 5 to 6 inches from heat 2 minutes or until cheese melts. Serve immediately.