Warm 1 tablespoon oil in a large skillet over medium-high heat until shimmering.

Pat the chicken thighs dry and season with salt and pepper.

Add the thighs to the hot pan. Cook 4–5 minutes per side until well browned and the internal temperature reaches 165°F. Remove the chicken and set aside on a plate.

In the same skillet, whisk together the brown sugar, soy sauce, hoisin sauce, sweet chili sauce, grated ginger, minced garlic, lime juice, and dried red pepper flakes to taste.

Bring the sauce to a boil, then lower the heat to a gentle simmer. Cook until slightly thickened and syrupy, scraping up any browned bits from the pan.

Return the chicken to the skillet. Spoon and turn to coat each piece; simmer a few more minutes until the sauce clings and reaches the desired stickiness.

Remove from heat and garnish with sesame seeds and chopped green onions before serving.