Warm the oil in a medium saucepan over medium heat. Add the chopped onion and rice, sautéing for 3–5 minutes until the rice turns golden.
Stir in the cumin, chicken broth, and black beans. Bring the mixture to a boil, then reduce the heat to low, cover, and simmer for 20 minutes.
Remove from heat and let rest, covered, for 5 minutes. Fluff gently with a fork and set aside.