In a blender, combine pineapple juice, white vinegar, lime juice, onion, garlic, cumin, oregano, cinnamon, salt, pepper, achiote paste, and guajillo chili powder. Blend until smooth and well-combined.

Place the chicken thighs in a large bowl or resealable bag and pour the marinade over them, ensuring each piece is evenly coated. Refrigerate for a minimum of 2 hours.

Heat olive oil in a large skillet over medium-high heat. Add the marinated chicken thighs in a single layer. Cook for about 8-10 minutes per side until golden brown and cooked through.

Once the chicken is nearly cooked, add the pineapple chunks to the skillet, stirring gently. Sauté for an additional 2-3 minutes.

Transfer the chicken and caramelized pineapple to a serving platter. Let the chicken rest for a few minutes before slicing and serving.