In a bowl, whisk together the orange juice, orange zest, brown sugar, soy sauce, ginger, and chili flakes.

Pat the chicken thighs dry with paper towels, then cut them into bite-sized pieces. Season with 3/4 teaspoon salt and 1/2 teaspoon black pepper.

Add the cornstarch, 1/2 teaspoon salt and 1/4 teaspoon black pepper to a large zip-top bag. Mix to combine.

Add the chicken to the bag, seal, and shake until the pieces are evenly coated.

Heat 3 tablespoons of oil in a large skillet over medium-high heat. Add the chicken in a single layer and cook until golden brown and cooked through, about 4 to 5 minutes per side. Work in batches and add more oil if needed. Transfer to a lined plate.

Pour the sauce into the skillet and bring to a simmer. Cook for 3 to 5 minutes, stirring frequently, until thickened and glossy.

Return the chicken to the skillet and toss until evenly coated in the sauce.

Garnish with sliced green onions. Serve and enjoy!