Saute diced onion in large skillet with oil on medium heat.
Once onion is translucent add ground beef to skillet. While beef browns place refried beans in bottom of 9x13-inch baking dish. Spread evenly. Cut and dice toppings, set aside.
When ground beef is browned, drain fat.
Add in chili powder, cumin, corn, black beans and diced bell pepper. Mix well. Place lid on skillet and simmer until bell pepper is softened.
Add salsa to ground beef mixture and stir well. Place on top of refried beans.
Bake for 15-18 minutes until heated well throughout.
Take handfuls of tortilla chips and loosely crunch in hand. Place on top of the ground beef mixture.
Layer with shredded lettuce, tomato, green onions, jalapeno peppers, and black olives to taste.
Serve immediately with a fresh cilantro, and a dollop of sour cream or guacamole.
Cover and refrigerate leftovers. This is best the day of.