Heat a large skillet over medium-high heat and add the olive oil.
Add the chicken pieces and half of the taco seasoning; cook undisturbed for 2 minutes, then flip and continue cooking 2–3 more minutes, stirring occasionally, until the chicken registers 165°F and is cooked through.
Remove the cooked chicken to a plate. Add the drained corn to the hot skillet in a thin layer and let cook without stirring 3–4 minutes to develop a char; then stir and cook an additional 2–3 minutes until golden browned. Remove the corn and set aside.
Reduce heat to low and add the Alfredo sauce, tomatoes with green chiles (undrained), milk, and the remaining taco seasoning; stir to combine and bring to a gentle simmer.
Add the tortellini to the sauce, stir to coat, cover the skillet, and simmer about 5–7 minutes or until the tortellini are tender.
Return the chicken and charred corn to the skillet, stir to combine and heat through.
Garnish with chopped cilantro and serve.