Set oven to 400° F.
Chop onion, garlic, and cilantro.
Bring water to a low boil. Cook tortellini for approx. 3 minutes. Drain and set aside.
Add oil to a medium sauce pot. Heat on medium/high heat.
Add onion and garlic and cook 2-3 minutes until onion starts to turn translucent.
Add ground beef and taco seasoning to the pan. Continue cooking until beef is fully cooked.
Add tomatoes and continue cooking for another 5 minutes or so until heated through.
In a separate bowl, combine tortellini, chili, black beans and half of the shredded cheese.
Fold together and spoon into a cast iron skillet or oven safe serving dish. Top with remaining cheese.
Cook in oven for 10-15 minutes until heated through and cheese on top is melted.
Top with cilantro and lime.