Season the boneless skinless chicken breasts with salt, pepper, garlic powder, and smoked paprika. Heat 2 tbsp olive oil in a large cast iron skillet over medium-high heat and sear the chicken until golden, 5-6 minutes per side, until cooked through to 165°F; remove and rest briefly.

Whisk pineapple juice, brown sugar, soy sauce, ketchup, garlic, and ginger in the same pan over medium heat. Bring to a simmer, with bubbles rising around the edges.

Stir in the cornstarch slurry (cornstarch mixed with water) and cook 2-3 minutes, until the sauce turns glossy and thick enough to coat a spoon. Add the pineapple chunks and let them heat through.

Return the chicken to the pan and turn to coat in the glaze. Cook 2 more minutes so the caramelized edges deepen and the sauce clings to the surface.

Let the chicken sit off heat for 20 minutes to let the sticky glaze set slightly. The amber sauce should look thicker and more cohesive.

Garnish with sesame seeds and sliced green onions for a fresh pop of color. Serve immediately over steamed rice while the glaze stays sticky.