While the Peppers are roasting – heat oil in a large skillet over medium/high heat. Add ground beef and season with entire taco seasoning packet. Allow beef to brown on all sides. Add diced onion – continuing to cook until softened. Reduce heat to Medium. Mix in the black beans, brown rice, corn, and salsa. Add in 1 cup of cheese and stir until incorporated and the cheese has melted. Remove from heat.