Preheat the oven to 475°F. Line a rimmed baking sheet with parchment paper or lightly grease it with oil.

In a large bowl, combine 1 1/2 pounds cubed boneless chicken breasts, 1 egg white, 1 tablespoon tamari or soy sauce, and 1 tablespoon orange zest. Toss until the chicken is evenly coated.

Place 1/3 cup cornstarch in a shallow bowl or pie plate. Working in batches if needed, dredge the coated chicken pieces in the cornstarch so each piece is fully coated. Shake off any excess cornstarch and arrange the pieces in a single layer on the prepared baking sheet.

Drizzle the chicken lightly with sesame or olive oil. Roast in the preheated oven for 8 minutes. Use tongs to flip each piece, then return to the oven and roast another 3–5 minutes, until the chicken is cooked through (internal temperature 165°F) and the coating looks set.

While the chicken roasts, make the sauce: in a bowl whisk together 1/2 cup tamari or soy sauce, 1/3 cup orange juice plus 2 tablespoons orange zest, 2 tablespoons honey or maple syrup, 1–3 tablespoons chili paste (use the amount you prefer for heat), 2 teaspoons creamy peanut butter, 2–4 cloves chopped garlic, and 1 tablespoon fresh grated ginger until smooth.

Remove the baking sheet from the oven. Turn the oven to broil on high. Pour the prepared sauce evenly over the roasted chicken on the baking sheet and use tongs or a spatula to toss and coat the pieces in the sauce, scraping any browned bits from the pan.

Sprinkle the coated chicken with 2 tablespoons toasted sesame seeds. Broil the sheet pan 1–3 minutes, watching closely, until the sauce begins to thicken and stick to the chicken and develops some color. Remove from the oven immediately to avoid burning.

If you like, tuck nori sheets into the hard shell tacos before assembling. Fill each of the 12 hard shell tacos with lettuce (if using), the sesame-ginger chicken, and your choice of kimchi, cilantro, green onion, and queso fresco or favorite cheese.

Serve the tacos with any extra sauce left on the sheet pan and with yum yum style sauce for drizzling on top.