Mist a medium nonstick skillet with olive oil spray and set over medium-high heat. Add the chicken. Cook, stirring with a wooden spoon and breaking into large chunks, for 4 to 6 minutes, until no longer pink.

Meanwhile, in a small bowl, combine the vinegar, Worcestershire, honey, and hot-pepper sauce. Whisk to blend.

Drain off any liquid that has accumulated in the pan. Add the onion, bell pepper, tomato sauce, chili sauce, chili powder, and the reserved vinegar mixture to the pan. Stir to blend.

Bring the mixture to a boil, then reduce heat so it simmers. Cook for 20 minutes, or until thickened.

Spoon the mixture equally onto the opened buns. Serve immediately.