Start by cooking 2 cups of rice according to the package instructions and set it aside. Preheat your oven to 400°F.
Then, pat dry the chicken and cut it into small pieces. Mix the chicken with the oil, teriyaki sauce, and kewpie mayo, and set it aside.
Cut the nori sheets into squares of equal size. Place 1-2 tablespoons of cooked rice onto each nori square, pressing it down gently with your fingers or a spoon.
Press each nori square into the cups of a muffin tin. Spoon 2 tablespoons of the chicken mixture into each muffin cup.
Bake them for 15-16 minutes, then broil for an additional 2 minutes to brown the tops a bit more. While they’re baking, prepare the spicy sauce by mixing together the mayo and sriracha.
Drizzle a little of the sauce onto each muffin, then sprinkle them with green onions and sesame seeds. They’re best enjoyed right away!