In a large skillet over medium heat, add the ground beef. Break it apart with a spatula and cook until it’s browned, about 5-7 minutes. Drain excess fat if necessary.
Once the beef is cooked, sprinkle in the taco seasoning. If you're using homemade seasoning, feel free to adjust the spices to your liking. Stir well to combine, allowing the flavors to meld.
Add the black beans, pinto beans, and diced tomatoes to the skillet. Stir everything together and let it simmer for about 5 minutes.
While the beef and bean mixture simmers, heat oil in a frying pan over medium-high heat. Fry each biscuit until golden brown, about 2-3 minutes per side.
To assemble, take a fried biscuit and spoon a generous amount of the beef and bean mixture onto it. Top with your choice of olives, sour cream, diced tomatoes, shredded lettuce, sliced avocado, and shredded cheddar cheese.
Serve your Easy Navajo Tacos warm, and enjoy!