Bring a pot of water to a boil and cook the udon noodles according to package instructions, usually around 6-8 minutes. Drain and rinse under cold water to stop cooking.

Heat a large non-stick skillet over medium-high heat, add sesame oil, and once shimmering, add bite-sized chicken pieces. Cook for about 5-7 minutes until browned and cooked through.

Pour teriyaki sauce into the skillet and simmer for another 2-3 minutes until thickened and coats the chicken.

Reduce heat to medium, add cooked udon noodles, and gently toss everything together for about 2 minutes.

Prepare bowls with cooked rice at the bottom and spoon over the teriyaki chicken and noodle mixture.

Garnish with sliced green onions and sesame seeds before serving.