Preheat your oven to 375°F (190°C) and prepare a baking sheet by lining it with aluminum foil.

Combine hoisin sauce, soy sauce, honey, oyster sauce, rice vinegar, minced garlic, Chinese five-spice powder, and sesame oil in a medium bowl and whisk until smooth.

Place chicken thighs in a resealable plastic bag, pour half the marinade over them, seal the bag, and refrigerate for at least 2 hours or overnight.

Transfer the remaining marinade to a small container, seal it, and refrigerate for later use.

Remove marinated chicken from the fridge and let it sit at room temperature for about 30 minutes.

Arrange the marinated chicken thighs in a single layer on the prepared baking sheet and bake for 25-30 minutes until fully cooked with an internal temperature of 165°F (74°C).

Pour the reserved marinade into a small saucepan, bring it to a boil, then reduce heat and simmer for about 10 minutes until thickened.

Brush the thickened marinade over the baked chicken, return to oven, and broil for an additional 2-3 minutes until caramelized.

Allow the chicken to rest for 5 minutes before slicing and serving.