Sprinkle the chicken pieces evenly with the taco seasoning.
Heat the oil in a 12-inch non-stick skillet over medium-high heat. Add the seasoned chicken and cook, turning occasionally, until browned and no longer pink in the center, about 5–7 minutes. Remove the chicken from the skillet and set aside.
To the same skillet, add the instant rice, milk, and thin salsa; stir to combine and bring the mixture to a boil.
Cover the skillet, reduce heat to low, and simmer for 5–7 minutes, or until the instant rice is tender and has absorbed most of the liquid.
Stir in the queso cheese dip and the undrained Rotel tomatoes until evenly combined, then simmer uncovered for 5 minutes to heat through.
Sprinkle 1/4 cup of the shredded Mexican cheese blend over the rice, return the cooked chicken to the skillet on top of the rice, then sprinkle with the remaining cheese.
Cover the skillet and cook over low heat just until the cheese melts, about 1–2 minutes. Serve warm.