Stir together salt, granulated garlic, onion powder, paprika, and black pepper in a large bowl until combined. Add chicken pieces, browning sauce, and allspice, stirring and tossing to evenly combine.
Stir in white onion, tomatoes, bell pepper, scallions, garlic, thyme, and ginger; mix until evenly distributed. Cover and refrigerate at least 30 minutes or up to 12 hours.
Remove chicken from marinade, letting excess drip off. Reserve marinade.
Heat vegetable oil in a large Dutch oven over medium-high until shimmering. Working in 3 batches, add chicken pieces to hot oil, and cook until chicken is browned on all sides, 3 to 4 minutes per side. Transfer chicken to a plate.
Reduce heat to medium; add Scotch bonnet pepper and reserved marinade to drippings in Dutch oven. Cook, stirring occasionally, scraping any browned bits on bottom of Dutch oven, until vegetables are soft, about 5 minutes. Add browned chicken, chicken stock, and ketchup; stir until ketchup dissolves, about 30 seconds.
Bring to a boil over high; reduce heat to low, cover with a tight-fitting lid, and simmer, stirring occasionally, until chicken is tender and cooked through, 30 to 35 minutes. Spoon off and discard fat; discard thyme stems and Scotch bonnet pepper before serving.
