Steak Fajita Power Bowls

Name: Steak Fajita Power Bowls
Ingredients: 2 tbsp. vegetable oil, divided; 1/2 yellow onion, sliced into half moons; 2 bell peppers, seeds and ribs removed, thinly sliced; Kosher salt; Freshly ground black pepper; 1 lb. skirt steak, cut into 1/2 slices; Juice of 1/2 lime; 1/2 tsp. chili powder; 1/2 tsp. cumin; 4 c. cooked brown rice; 1 avocado, thinly sliced; 1 c. black beans, drained, rinsed; 1 c. frozen corn, thawed, warmed; 1 tbsp. finely chopped fresh cilantro; Sour cream, for serving