Place a large cast-iron skillet over medium-high heat and add the avocado oil.
Once the oil is shimmering, add the diced red onion and bell peppers, sautéing for 3-4 minutes until the edges are slightly caramelized.
Add the ground venison to the skillet, using a wooden spoon to break the meat into small crumbles.
Sprinkle the chili powder, cumin, garlic powder, sea salt, and black pepper evenly over the meat and vegetables.
Continue cooking for 5-6 minutes, stirring occasionally, until the venison is fully browned and no longer pink.
Lower the heat to medium and stir in the black beans and cooked brown rice, tossing well to ensure every grain is coated in the spices.
Cook for another 2 minutes until the beans and rice are heated through, then remove from heat.
Divide the mixture into a bowl and top with freshly chopped cilantro and a bright squeeze of lime juice.