1. Preheat oven to 350 degrees F. Grease a large baking dish with cooking spray; set aside.
2. Grease a large nonstick skillet with cooking spray. Heat over medium-high heat. Add onion, beef, pork, black pepper, and chili powder. Cook and stir, breaking up meatuntil its cooked through, about 5 minutes.
3. Add jalapeqos and cheese. Reduce heat to medium-low. Cook and stir until cheese melts. Remove from heat.
4. Add half the chips to prepared dish. Top with half the meat mixture, 1 cup of the grated cheese, and half the olives. Add remaining chips, piling them in middle of dish. Top with remaining meat, cheese, and olives.
5. Bake nachos for 10 minutes. Top cheese will brown slightly.
6. Garnish nachos with scallions and avocado. Serve immediately with sour cream and salsa on the side.
Do-Ahead Tip: You can prepare the meat mixture, without the cheese, up to two days in advance. Cover and refrigerate. Heat through on low heat before assembling nachos.
Source: Hannaford fresh Magazine, January - February 2008