Heat oil in a skillet or saute pan over medium-high heat. Add rice and cook, stirring occasionally for 3 or 4 minutes, until lightly golden brown. Reduce heat to medium and add the onion, potato, carrot, and garlic. Season with taco seasoning and 1/2 teaspoon salt. Cook and stir for about 2 minutes. Add the tomato sauce; cook and stir for a minute or two and then slowly stir in the chicken broth.
Return heat to medium-high and bring to a boil, then reduce heat to low, place a lid on the skillet and simmer for 25 minutes. Remove from heat and allow to sit for 5 minutes, covered. Remove cover, fluff with a fork, garnish with cilantro (optional) and serve.
Optional: Add additional vegetables like frozen corn or peas (thawed), mushrooms, zucchini, bell pepper in addition to or instead of the potato and carrot.