Preheat oven to 375°F. Grease a 9×13-inch baking dish.
Warm oil in a large skillet over medium heat. Soften onion 3–4 minutes, then stir in garlic for 30 seconds.
Brown the ground beef, breaking it up, until no pink remains. Drain excess fat.
Stir in taco seasoning, broth, and salsa. Simmer 2 minutes to bloom the spices.
Fold in beans, corn, and green chiles. Cook 3–4 minutes until slightly thickened. Season with salt and pepper.
Remove from heat. Stir in sour cream and half the cheese until combined.
Spread the mixture into the prepared dish. Sprinkle with the remaining cheese.
Bake 12–15 minutes until bubbly and the cheese is melted.
Scatter crushed corn chips over the top. Bake 3–5 minutes more to crisp.
Rest 5 minutes. Add lettuce, tomatoes, green onions, cilantro, and jalapeños. Serve warm.