Pat the cubed chicken dry and toss with one-third of the taco seasoning (reserve the rest).
Heat the olive oil in a 12-inch non-stick skillet over medium-high heat. Add the seasoned chicken and cook 2–3 minutes per side until lightly browned and cooked through; remove chicken from the skillet and set aside.
To the same skillet, add the orzo, chicken broth, enchilada sauce, undrained Rotel, and the remaining taco seasoning; stir to combine and bring to a boil.
Reduce heat to low, cover, and simmer 15–20 minutes, stirring occasionally, until the orzo is tender and most of the liquid is absorbed.
Stir in the sour cream, drained corn, drained and rinsed black beans, shredded cheddar, and the cooked chicken; mix until heated through and the cheese melts, about 3–5 minutes.
Taste and adjust seasoning as needed, then serve hot.