Make the jerk spice paste: In a small bowl, stir together 2 teaspoons dried thyme, 2 teaspoons ground nutmeg, 2 teaspoons ground cinnamon, 2 teaspoons ground allspice, 2 teaspoons ground ginger, 1 teaspoon ground black pepper, and 1 teaspoon kosher salt.
Add 2 tablespoons extra-virgin olive oil to the spice mixture and mix until it forms a spreadable paste.
Place 3 pounds boneless, skinless chicken thighs (trimmed of excess fat) in the bottom of a slow cooker. Rub the spice paste evenly over all the chicken pieces.
Sprinkle the white parts of the chopped green onions over the chicken (reserve the green tops for serving).
Pour 20 ounces pineapple chunks (with their juices) evenly over the chicken, then add 1/4 cup white vinegar.
Add 6 chopped garlic cloves and 2 diced jalapeño peppers (with seeds) to the slow cooker.
Cover and cook on low for 4 to 5 hours, until the chicken is tender and cooked through (internal temperature 165°F).
Using tongs or a slotted spoon, transfer the cooked chicken to a plate and shred with two forks. Use a slotted spoon to remove the pineapple chunks from the cooker and set them aside.
Pour the remaining cooking liquid from the slow cooker into a wide saucepan. Heat over medium-high and stir often until the liquid is reduced by about half and slightly thickened, about 5 to 10 minutes.
Return the shredded chicken and the reserved pineapple chunks to the saucepan and stir to coat with the reduced glaze; heat 1–2 minutes more to combine.
Warm the corn tortillas in a dry skillet over medium heat until pliable, about 20–30 seconds per side.
Assemble tacos: fill the warmed corn tortillas with the glazed chicken and pineapple, then top with reserved green onion tops, shredded red cabbage, crumbled feta cheese, and a squeeze of lime from the lime wedges.