Preheat oven to 400 degrees.
Apply cooking spray to muffin pan. Using a 2 1/2-inch circular biscuit cutter, cut a circle out of each tortilla. In a small saucepan, heat the oil. Quickly drop each circle into the oil, allowing it to cook for 2 seconds. Remove from oil and press into the inside of a muffin pan. Bake for 8 minutes. Remove from oven and let cool on a paper towel.
In a skillet, brown the ground beef, add taco mix and water. Simmer until slightly thickened, reserve.
In separate containers, microwave the refried beans and cheese dip in 45-second intervals until hot.
To assemble the nachos: Layer each cup with 1 tablespoon each of refried beans, ground beef and cheese dip. Top with shredded lettuce, 1/2 tablespoon each of sour cream, tomato and minced onion. Garnish with cilantro.